I have had good luck with Adorama items on eBay, but have the luxury of paying/picking up in person, so I can make sure it's been accurately described. It's been my experience that they grade fairly on most things. One exception was a Deardorff V8 that was 'excellent' on their website, but when I went in to see it, it was way, way overgraded. That was three years ago, and of late they've been very good about grading.
Neal