I always thought of Ira Gitler as a very articulate bebop "superfan", not really a critic. He loved this music and it came through in his writing, and made it a pleasure to read. I'd much rather read his liner notes than those by some of his more polished contemporaries. If I had to analogize, he reminds me of Bill Simmons.
I think when he shifted into "critic" mode he was on much shakier ground but, who cares.