Is this the quality you get with PETG?  

belt tension tool

Believe Dan,  the gent with the brown dog in pic, confirmed that the tool printed in other brands of PETG gives different results.  I've used the tool printed in prusa petg and to does work great.

Posted by: @fuchsr

The readings are only valid if printed with Prusament PETG.

I know that's that the description says. And it's what I have done myself. But I'm wondering if anyone has actually confirmed that experimentally? I can certainly see why i can't substitute PLA, but I'm wondering what would make Prusament PETG special. Sure, I can see how additives can make a difference but to what extent? I'm out of town but I may give Overture PETG a try, just to see if it indeed matters. 

Here's the file

So here is my next attempt to send you the .3mf file.

Google for filament dryers

What do you think about the cheap dryboxes from Amazon (eSUN, Sunlu)? Some reviews are fantastic, others state that the boxes don't even nearly reach the temperatures they are advertising. A "professional" filament dryer or food dehydrator for over 100€ might be a bit over the top for a beginner and (at least atm) hobbyist, what do you think?

(Btw: I got my Prusa MK3S for nearly a year now and wanted to start doing things beyond statues and toys that don't really need the precision I am looking for now.)

@lukas-6

When you start having trouble, go back to standard setting and work your way from there.

I will print two of them tomorrow, one with your setting and one standard setting. 
It is midnight here in Sweden now 😴 

Experimentally verified

I have done the tests and side by side comparisons.  Prusament PETG is stiffer than regular petg for the most part (I only have about 5 brands to compare).  Prusament PETG will read lower than the generic counterparts.  Thus is you print the part with other PETG the readings will be higher - and you may be under-tightenign using a "false" petg.

Posted by: @lukas-6

What do you think about the cheap dryboxes from Amazon (eSUN, Sunlu)? Some reviews are fantastic, others state that the boxes don't even nearly reach the temperatures they are advertising. A "professional" filament dryer or food dehydrator for over 100€ might be a bit over the top for a beginner and (at least atm) hobbyist, what do you think?

(Btw: I got my Prusa MK3S for nearly a year now and wanted to start doing things beyond statues and toys that don't really need the precision I am looking for now.)

 test_print_petg.zip

See the video here and here , where most popular dryer are compared.
My opinion... Dryer is a long term decision and should be usable for all kind of filaments. The problem is, filament dryers are quite overpriced for what they are. And many aren't even proper dryers.
I use food dehydrator: is half the price and has excellent drying capability. The only downside is (not for me though), it can't be used on filament while printing.

A "professional" filament dryer or food dehydrator for over 100€ might be a bit over the top for a beginner and (at least atm) hobbyist, what do you think?

It very much depends on your circumstances. I've printed for years without dry boxes. But this year was a year of crazy humidity in our area, and using a dry box made a real difference. It also depends on how quckly you turn your filament over and how you keep it while not in use.  If you go through a spool of PLA in a day, no need to dry it. Sure, you may end up with a lemon - wet filament right out of the vacuum bag- but I found this to be rare. It's more likely you need to dry filament when it's been sitting for an extended period under suboptimal conditions. But then again, this year I had one particular color of Prusament PETG that printed fine in the morning and bad by the end of the day. And then others such as TPU benefit from printing right out a drybox, which is one advantage of the dedicated boxes  compared to a regular food dehydrator. 

It is hard to get a good picture.
Right one is original file, no changes at all
Left is Prusa standard settings White Prusament PETG

There is no significant differences between the two as I see it

It is hard to get a good picture.

Yes that is indeed a problem. Depending on the angle the cubes sometimes look horrible (like in the second picture i posted), or they look glossy and fine. Here is a picture of the same surface i posted yesterday but from another viewing angle.

There is no significant differences between the two as I see it

I only changed the standard settings in a minimal way. I don't think it makes any difference for such simple structures ... but who knows, hence i sent the .3mf.

To be honest ... I don't think your cubes look that much better than mine? I can see similar irregularities in your surface, especially on the corners? Some layers also seem to be more or less squished than others, what do the others think?

I should have written that in a different way

I don't think your cubes look that much better than mine

Please don't take any offense by that. It is what my uneducated eyes see. I am here to learn so please correct me if I am wrong 🙂

No worries 😀 

I think mine looks a little better, but, I compare your pictures with my cube, and you compare my picture with your cube. So, who knows 🤔 

The problem is more that you've Had good prints, and now you don't. 
And it is happening, as I understand it, with all filaments.
So something is happening over time with your printer.. 

A little update and a new question

Ok so here is a update on my search for problems. 

I decided before I invest a lot of money into some filament dryer or food dehydrator (which i WILL do in the future for sure), i would like to eliminate hardware problems.

Hereby i noticed that the trapezoid nuts have - in my opinion - a lot of tolerance maybe about .5mm on the Z axis threaded rods. I disassembled the Z Axis (and am using this off time to clean and grease the bearings also on X and Y) and noticed that the trapezoid nuts don't look like I remember them. They look greasy and a bit rough on the inside. 

Is this normal for this material which I read would be self-greasing? Are the tolerances normal? I was asking myself why the printer is not equipped with brass nuts, is it just because of a higher noise level or is there some mechanical advantage with the plastic ones apart from more some higher maintenance for lubrification? 

Play in the trapezoid nuts would be bad ...

How many hours have you run this printer?

Compare to the spare

You should have at least one spare trapezoid nut to compare to

I did not receive any spare trapezoid nuts. I got this printer pre-assembled, maybe they don't include one in these packages.

I am running the printer since pretty exactly a year now. I can't tell how many hours exactly since I reset it to factory settings after some months of use (tried to calibrate E-steps for higher accuracy and messed up - d'oh -, wanted to start fresh). Roughly estimating ... maybe around 800 hours? Maybe less ... something around that.

It's a wear part

Yeah, if you have been hammering it, or your Z bearings got stiff, the trapezoid nuts could wear.  I think it is a printable part if your printer isn't too far out of whack.

Yeah, if you have been hammering it, or your Z bearings got stiff, the trapezoid nuts could wear

Do you think that it could cause the problems seen in my prints? I mean yes, I maybe should apparently change them anyways, but could there be a real benefit for the problem I am facing right now?

I will send a short clip of the play in the nuts in the evening to clarify my point of view.

Which Prusament PETG exactly ...

..do you use?

Did you print from PETG before and it was OK , or this is your first attempt?

PETG

When you look at your printer, it is also printed from PETG, sou you can have a real comparison. 

You will always see some leayers unless you do some postprocessing. I use PETG for practivcal printed parts, so the perfect surface is not always the most important.

Do you think your print from PLA are smoother?

Posted by: @zoltan

...You will always see some leayers unless you do some postprocessing...

-that's very important to keep in mind (visible layers just can't be avoided with printing filament). The goal we wish to achieve is, that layers are equally distributed (height and thickness), without visible glitches.
Next thing to keep in mind, is the fact, that printing result will also depend on printed object. That is, if I print certain part perfectly, then that doesn't mean, that the next (totally different shape & size) will also be perfect. And that's why settings in slicer exist, I think one should make at least two profiles for PETG: one for smaller (detailed) objects, and one for larger (stronger) objects.
By keeping above in mind, I can say I get very similar results with PETG and PLA. Ok, PETG is slightly more stringy, but that can be easily removed (burned). Actually I kinda became PETG fan and I'm seriously considering to use PETG for everything (PLA only when there's really a reason for it).

Just sharing my experience...

PETG

I am also a PETG  (for some models ASA) guy 😉 . Elaborated also with PC Blend.