I've had one since the beginning of the month. It is a fun, low-recoiling, extremely accurate handgun. As the other users commented, the ammo is pretty expensive right now but the situation is improving as more people are getting into them. Overall, I've been pretty pleased with buying it, I have no regrets.
I'm probably going to jump on a waiting list for the PS90 too. I was initially not so hot about the 5.7 round; as I've learned more about it and its specific niche, I've gained a great deal of respect for it. If nothing else, FNH has brought something new to the market that isn't a 1911 or AR-15, and I think they need to be rewarded for that.
The fivensevenforum is a great place to find more info about the 5.7x28 platform out in the world. Stop by and say hello!