On the plus side it is a big book with a ton of Parker solos in it. It makes for great sight reading and makes you appreciate the genius of Parker. It is worth having for any aspiring improviser. That said it isn't a book ot technical studies. It doesn't cover all keys and it isn't laid out for efficient practice. There are a ton of techincal study books out there and I'm sure people will list their favorites. I'll put in a plug for Walt Weiskopf's "Around the Horn" It is well organized and written with jazz improvisation in mind.

I have the Omnibook, and I guess it totally depends on how good you are at sax. I can only play like 2 of the songs so far because articulation insn't marked. It's a great book though, and it's totally worth it. You should also buy some of CP's CDs because that book is really really really hard if you don't know what the solos sound like. Good Luck! Kara