I have a prusa M4 with multi-material head, and I am super happy with it. It started as a M3, and has been upgraded twice to become what it is today.
It was expensive, but prusa really does have great support for free, which is worth a LOT. And the upgradability means you end up spending less if you keep with the hobby over years.
But one caviat, I have the printer set up and my friend's house, because he has more space and free time. So most of what I know about it comes from his experience, not mine. I do lots of CAD, but I don't often actually touch the printer myself.
I think it is mostly the massive success. Some people have a belief that anything that is very popular is by definition bad.
https://headstuff.org/topical/love-hate-popular/