His style is pretty unique. He grew up as a flamenco player in South America, and he uses the flamenco technique on the bass. I discovered him in the early 90s on a Ron Kenoly praise CD. He's been a big deal in the jazz scene since probably the 70s though. He used to play with Henry Mancini and other really big names from that era.
His son (Abe, Jr.) is a well-respected jazz drummer. There is a video on youtube with the two of them jamming in a club.
I like Les, too, but wish the band's music was more diverse.
Oh, and Victor Wooten's interpretation of Amazing Grace on Bela Fleck's "Live Art" CD is unbelievable.