I did a late season Lodore trip last year and a couple guys R2'd a Minimax with all their gear including drybags and a cooler. It seemed like they had a blast and that they could make it go wherever they wanted. No problems with it flipping.
Alternately, I went on a Yampa trip this year and this guy Larry had a 1st generation Aire Puma. He said it was a bit smaller and slightly different design to the current one, but it did great and he also seemed to be able to move that thing wherever he wanted on the river. Here is a video of him in action on Warm Springs rapid at ~14-16k cfs(second blue/teal boat)...
In that category, for me, it would be hard to not look at the Rocky Mountain Rafts Storm raft. It is their equivalent to the Mini Max and is significantly cheaper. They are both import rafts so that isn't an issue. The PVC on the RMR rafts is harder to roll and a bit heavier compared to the Hypalon or Neo Hyside, but both seems to hold up well.
I guess the last thing I'd say is that its relatively rare to see the small size Puma on the used market. There are plenty of them out there, so its not because they aren't well liked but more because they are so well liked that people don't sell them. Seems more versatile to me, but if you are just looking to get out R2ing then the Mini-Max or Storm might be better. You see come up more on the used market then the Puma, but they also seem to hold their value too. I know a couple places are doing end of season specials on both, so its good time to buy new setups too.
Either way, I don't think you can go wrong with any of them. They were all a bit small for my taste as an oar rig, so I opted for a 12' Hyside that I got recently to supplement my 16' Avon Pro gear hauler.