I've loved my Phat Cat. I own a rafting company and have access to lots of craft. I typically kayak and am pretty comfortable leading new runs at class V levels. I rarely raft for fun. It's just not my scene. The Phat Cat paddles like two kayaks strapped together. Snappy eddy turns, boofs, surfs are all kayak level easy and natural to the PHat Cat in ways that will never happen in a regular raft. We've boated Gore at 600-1500cfs, Bailey to 600, Barrel Springs, Westwater, surfed and ran many other sections. It's surfs unbelievably well both in the park and in the field, so easy you can drop your paddle and move around the boat. We've never flipped one yet in all our trials. We've never wrapped. That's over atleast 8 Gore runs alone (never flipped at Tunnel either before you ask). We've now got 3 Phat Cats at the company owned by me and our top guides. For running big, difficult water, or tight creeks typically reserved for kayakers it simply cannot be beat.
Compared to other paddle cats - well, why pay more? The fabric and build is bomber and has my complete confidence. Plus the tube size is quite a bit bigger than the competition, that allows for a drier, higher ride and more kick in the tubes. We've never stuffed a wave!
Compared to rafts - Cats can't payload much before the cross bars start dragging in the water, at which point you are effectively paddling a poorly designed raft. Don't plan on using it for a heavily laden multiday unless you are solo. Two dudes and a drybag are about all you will want in there. So it can't multiday or party barge the way a 13' raft can. For this reason its not as versatile as a 11-13' raft, thats the big drawback.
R1 - This thing is fabulously challenging to run R1. Class III becomes something worthwhile again. I learned more R1'ing this boat than I had on the river in a very long time. It's without a doubt made me a better boater.
Framed - I don't have a frame for this, but we aspire to get one to use as a training platform for new guides (since our rafts are all framed). Frankly I suspect it will be less fun framed, but that's just conjecture so do as you will.
So if you're a rafter that wants to charge class V or a kayaker who wants to bring a friend, go for it!