Technical advise.  

RE: Technical advise.

You are asking machine design questions.    There are a lot of opinions on printer design, but few have machine design experience.    I would not avoid a machine that has rods.   They are one of the easiest ways to get a precise diameter and straight surface.    Rod columns are used on precision NC machines.    The key is the rod diameter big enough.  Prusa changed the Z rod to 10mm diameter on the MK4 to stiffen the machine.   

Wheels on an extrusion?  Has the extrusion been machined?  What is the tolerance that was held?  What tolerances are held on the extrusion?  Wheel deflection, bearing  durability and many more factors determine life and accuracy.  

Neither would I dismiss a bedslinger for a core XY machine.  Prusa has a blog where they mention the problems of core XY machines that was suprising to many, belt stretch on long belts, slack from bearing wear and more.  

Prusa works well to assure good grade parts.  They will even wait for good parts, something many companies may not do.   In todays supply chain this is critical for a good product. 

Then there is tempurature.  The temperature may vary on our machines 20C.   How does that effect the machine.   Example a steel rod 300 mm long will change length by .08mm with a 20C temperature change. Aluminum will change by .15mm.  How does the design handle this? Twist, bend, give?  I know most don't consider temperature, but I was in an industry that held 0.002mm tolerances and temperature fluctuations can scrap parts. 

I have an MK3S+ that is now an MK3.9 and also a MK4 with a MMU3 that is working well.    I will admit the original MMU2 was not great, but the problems I saw were fixed in the MMU3. 

Many have run a Prusa for years with regular (3-6 month) standard oiling and cleaning.   Also Prusa still updates firmware on many older machines.   The Prusaslicer is well suported. 

As for the Forum complaints, this is normal for a forum.   In some other forums comments are watched and may be deleted.    I think there may be a schill or two on the forum also.  Ones that point out brand B is better than Prusa all the time.   Many of the big sounding problems have a simple answer.   For me it was an incompatible USB3 drive that many users said would be ok.  It caused problems, I went back to a good grade USB2 which is what the Prusa recommends.  Problems gone, but there was some discussion in-between.    We try to help others, the forum is nice but it usually takes many iterations to get to an answer that a face to face discussion would do in a few minutes.   

I have tried a cheaper 3D printer route, it was not a good experience.   I look for quality, on going support and ongoing software support.  Also can I use supplies from anywhere or am I locked into 1 supplier?   Prusa may not be the cheapest, but the MK4 works well.  I spend my time printing, and very little fiddling with the machine.   

RE:

Regarding choosing a printer - some people say that you should ask yourself a question: do yo need a tool or a project? Some brands and printer models are known to be limited and turn into a project because you have to bring the printer to the operational level.

I chose Prusa and though it is much more expensive I know people having other printers and I am lucky that it just works like a tool, even though I was aware I may get some issues due to the way Prusa Mini+ is designed and what problems it can generate -luckily I have no issues with my model and I am very pleased by it.

From the time experience I would rather get MK4S now due to the things I sometimes want to print and print bed is just a bit too small on the Mini.

Regarding forum activity - when you enter the hospital then you meet a lot of I'll people, because healthy ones do not have much if a reason to stay there. So this is similar to the forums, where your cognitive bias is shifted and you will experience a lot of people raising their voice because they are dissatisfied or don't know certain things.

Yet on other communication platforms I know a lot of people that got the printer and the fact that it works means they do not have to interact with others to say how well it works - this is especially the case on the forums where it takes a lot of effort for some to post with pictures. I think the best way to check how good certain things work is a section of Awesome prints ( pretty silent recently) and printables.com and makes section where people post pictures of the models and details what was used to print it so you can compare certain details yourself.

There is also a discord server for chat with various people with various experience and age, and trust me you would not be alone there 🙂