MMU2 or Palete 2  

RE: MMU2 or Palete 2

Both have issues. 
both have followers,

to a great extent it's a case of which you think is better for you

If you need 5 filaments then the pallette2 is probably not for you. 
If you only need 2 filaments then both are contenders, 
If one filament is sat PLA and the other is PETG you may find that the Pallette2 is unable to create a satisfactory joint between the dissimilar materials (the inter filament bond quality between these two materials is not good. )
If it's likely that you will need to use multifilament with a NON Prusa Printer Pallette2 may be the better option.
Support wise, there is likely to be more support for the MMU2, Here, than the Pallette2. 

Owners of working MMU2 will direct you that way, owners of working Pallette2 will direct you that way. 
Owners of problematic mmu or pallette will swear you off them... 

Often the failure is promoted by the approach of the user,  slapdash assembly of the MMU2 is likely to lead to dissatisfaction...
I have never had a pallette2 so I don't know what the most common self inflicted errors are, 

It's very much a case of, Are you feeling Lucky!   I have both the MMU1 and MMU2, working. some people were unable to get either working... 
regards  Joan

RE: MMU2 or Palete 2

I have both.  My frustrations with the MMU2 are documented in this forum if you search by my name. 

I tried everything and finally gave up.  In the months that I worked with the MMU2, I only had 1 successful print.  I know that other people on this forum have had many successful prints, and I respect that.  I tried everything that was suggested by people here, but my success rate never improved.  I came to the conclusion that I would rather enjoy the hobby than be constantly frustrated, so I removed the MMU2 from my system and went back to single-color successful printing. 

I then decided to give the Pallet2 a try.  I've had it for two months now and am over the learning curve. The Pallet is a well-built device. Right out of the box, I was able to immediately print several 4 color models (it supports a maximum of 4 filaments as opposed to the MMU2's 5). Overall, without a single modification, I have been able to print at about a 75% success rate.  It isn't perfect, but, for me, it is much better than the MMU2.  The 2 biggest issues with the Pallet2: 1) The filament path is very self-contained and feeds the filament via a curvy buffer.  If your filament is at all brittle, it will break in the buffer. The software isn't sophisticated enough to detect the error and will just act like it is still feeding the printer when it isn't.  You end up with the printer beeping because it ran out of filament, but the Pallet thinks everything is OK so there is no way to recover.  You have to reset the Pallet, clean the filament path, then start over.  There is no way to pause, then resume.  2) The online slicer (Canvas), is way inferior to Prusaslicer.  The same STL sliced with Canvas often fails, where it is successful with Prusaslicer. There is a way to use PrusaSlicer with the Pallet, but it isn't as nicely integrated as just using Prusaslicer.  However, Canvas has an interesting feature that allows you to take an existing mono-colored STL and "paint" it, then convert then export the painted model to the Pallet to create a multi-colored print.  It is still very much a beta feature...it works, but it is also quirky. Also, with the Pallet, I strongly recommend using Octoprint as the g0-between between the Pallet and your printer.

If cost is your consideration, the MMU2 is about half the price.  If reliability is important, the Pallet is a better solution; better, but not perfect.  Neither solution is problem free.

Hope this helps.