It's only been a few days and I haven't pushed it (I normally only use a few EW sounds at a time anyway), but it's working great for me so far. It's a HUGE relief. Before, I had all my VSL libraries on a Mac Pro slave with VE Pro, working great, with Play alongside Sonar on my Windows XP master, and was constantly having trouble with Play taking over CPU resources, missing notes or sustains on export, etc. Whether it's just finally getting Play onto a slave rather than the master computer, getting it onto a Mac rather than PC, or some other improvements they've done, it's totally working great. There's been much less swearing in my studio this week. :)
Of course, to stay on topic, it's thanks to VSL and VE Pro that I can do it! And VSL is still the vast majority of my sound. I pretty much only use EW for instruments VSL doesn't offfer.