Simply the best sounding pianos out there right now.
This is an enormous sample set. Out of the five pianos here, the largest is the Bechstein, which weighs in at over 80GB. Even using the Direct From Disk capability, this piano's full articulation version takes up just over 3GB of RAM, so unless you're running a slave machine or an x64 based host, you are going to have to do some tweaking to run it.
Thankfully there is a neat sample purge system which allows you to play the song once, then purge the samples that aren't used in the track. This frees up memory. And there are some lite versions that allow you to compose before plugging in the big brother for a full rendering to audio.
But it's all worth it. The sheer depth and the quality of the sample sets make them sound really dynamic and rich in detail. Now the ball is definitely in Synthogy's court to see if they can follow up with Ivory 2.
Play itself has been getting a lot of stick. It can be finicky to install, and the support forum isn't as open and transparent as it could be. There was one issue regarding losing favourites where the support team would only PM out the solution, but this has (thanks to some user pressure) now been made a sticky thread.
The 1.1.6 version of Play now seems much more stabie than previous versions. It works well and crash-free on my rig, which runs SONAR X64 on Vista X64. I can load up the full Bechstein piano and three other instances of Play with StormDrum 2, Voices of Passion and Gypsy all at once and still keep latency at 5ms at 24bit 88.2KHz. (It helps to have a big box full of RAM).