I've been playing with Oslecamo's Thri-Kreen in a campaign for quite a while, now. He's actually one of only three or so original characters since the campaign started.

I've noticed very little difference between a Thri-Kreen and a revised Thri-Kreen with to class levels (with the exception of class features). It seems to be doing its job very well, and I have no complaints. Good work, indeed.