I've been using the Silver and Gold versions for years. The Silver has a wonderful sounding Grand piano which is strangely missing from the Gold. Silver is much lighter on your drive and using resources.

As with most libraries, the Strong elements are percussion, and Strings, Woodwinds are OK, the brass is weak.
If you are a serious composer and want amazing orchestral sounds, check out the following>

LA Scoring Strings>wonderful library of expressive strings in sections and divisi. Pricey, but I would put them above both Vienna and East/West right now. At the end of January, a new String library is coming out that is supposed to wipe everything else out. It is called Hollywood Strings and was done completely on a Hollywood scoring stage. LA is $1,300 and I assume the new HS library to be at least $2,000, plus you would need a HUGE fast hard drive and tons of ram.

Sonivox, this library is amazing, with a $2,500 price tag to boot. This MAY be the most convincing library available at the moment. All elements are strong, with only the brass being still slightly static.

Wallander Instruments>This is the only physically modeled library that I know of, but there are some amazing brass and woodwind sounds here. The price is much less than those above.

You can do a google search of those libraries above, listen to the demos. We are at a crossroads between Sampling, scripting, and physical modeling. It will be very interesting to see what things look and sound like in 1 or 2 years time!

Ed