There's something about the aebersold collections that are just totally un-groovy. The jam tracks are just so wooden that your solos end up really static and non-exciting. His band are totally a group of jazz-robots.

I really do not recommend buying his books/cds. Jazz is such a social music and you'll only get good at jazz soloing by playing with other people.

I also recomment transcribing and/or learning to play your favourite jazz solos (not necessarily guitar solos) Start easy (Miles Davis), and work your way up (Wes Montgomery)