Yeah, primes tend to be sharper. I love primes even though I've only had a few. My best shots have been with a prime lens.
KEH is great. They rate everything but they are very conservative in their grading. It's not uncommon to get something that's listed to be in fair condition and it actually be in excellent condition. Anything that's listed as excellent or like new is good to go and if there's an issue, they will take care of it.
Camera Pimp member #1