I have EastWest Symphony Orchestra Platinum. it's the big package with the 16bit/24bit and 3 mic positions.
I was "using" is with Sonar X1d pro and the Play 3 engine. it worked maybe 50% of the time. I was running a duo2core quad 2.4ghz with 8gb ram. it was sluggish, crash prone and just frustrating.
I've upgraded my computer to a i7 quad 3.5ghz with 16gb ram and Sonar X3b Pro and Play 4.1. it's not "as" sluggish (personally I think you could throw 64gb at PLAY and it would be sluggish, I've only had 2 crashes so far and that I think was my fault throwing too much at it - user error). I still find PLAY frustrating.
now that I've had some time with PLAY and EWSO if I could go back in time....I would buy Orchestra Essentials.
if you DO want to play in the EastWest library world I would highly recommend waiting to purchase any of their products ONLY when there is a HUGE 50% off sale - which they seem to run 2-3 times a year from what I've seen.