mini is an in-line poppit (the bolt and most other mechanics are all in the same carrier, so it looks like a poppit)
I had it and I liked it, but it was a gas and battery hog. Maybe that could be different with some tinkering. But it was reliable. It never crapped out on me for mechanical reasons. It's easy to understand and it's easy to maintain. It was my first gun, and I knew nothing of how paintball guns worked. I simply took my mini apart and everything made sense.
That said, it's small. Some people like that feeling of carrying around something that'll give you a nice tight stance and small profile. I'm a big dude so it was weird.
My friend had an Etek 3 and I still love it. Feels high end but for a good price. It was just loud as hell lol.
I have not heard great things about proto guns, a lot of people report them breaking or something going wrong. If it's such a common occurrence idk if it's always user error.
I tried the Dangerous Power FX and it was an extremely well made gun but it did have some mechanical issues. The board puttered out after 3 games in the rain, and the ASA was leaking non-stop. Just a slight hiss the whole time. Not too much air lost but it was annoying and discomforting.
TL;DR - Planet Eclipse is highly recommended. Good electric hoppers: Halo B or Halo Too.