The SSL bundle is Waves' crown jewel, their finest achievement. At least, that's the opinion of many pros who have used it for years. If you're curious about whether its worth the price, why not download the demo? It should be immediately obvious to you how it compares with similar tools.
In my experience, no other SSL emulation matches Waves' snap and punch. Their may be some that sound more open and transparent, particularly on isolated tracks or sparse mixes, but in a modern dense mix the Waves plugins may help gel things together better. Try it yourself and see, as results will vary according to your tastes and material.
Cheers,
Eddie