I've only had 2 PT sessions in the pool so far, and am now just 5+ weeks since surgery. I think they wanted to give it a try since my early ROM is limited (28 degrees early last week). The first session was with some waterproof hiking shoes (made for stream crossings) and they are strongly buoyant. Second session was barefoot. So they were very different sessions, with the same exercises. The therapist thinks barefoot will be better from here on.
My impression is that it has a lot of potential and my first 2 sessions were good; the second noticeably better than the first. ROM measurement not retaken yet.
My notional plan is to alternate PT pool sessions with PT gym sessions, one each per week. Then do what I can at home every day. I have made up my own home routines with ideas from several rehab programs out there. I think that variety is very important, for flexibility and strength from all directions. My first progress check with the surgeon is not until mid-June, so we'll see what happens by then.
I'd say if you have a pool option, try it.