JK,
Though I don't think of them as "serious listening" I have enjoyed Spyro Gyra since I first heard them in 1978. I like their music and have played several of their tunes over the years with different bands. By the way, have you checked out any of the Yellow Jacket's lps? Though commercially successful, they have put out some very deep music!
For the record, I also have to agree with Mike:
However, "top notch playing" - compared to what? Compared to smooth jazz stuff? Sure, and I said as much. Compared to most rock folks? Sure, I'll go along with that. But compared to serious jazz players? Sorry, nope. When these guys were getting noticed, the Pat Metheny Group and the last versions of Weather Report were going. And there ain't no comparison in terms of the musicianship and musicality. SG is more in line with the Jeff Lorber Fusion - occasional nice stuff, but nothing monumental.
So, you asked your question, you got an answer you didn't like (from someone who isn't ignorant of the music). Why ask the question in the first place? You wanted 10 people to just say "Yeah! Spyro Gyra ROCKS!" ?
Mike
By the way, I have read many of your posts and am glad to have you as a member