I'll put in my 'vote' for KEH as well... I just purchased the (wrong) eye-level finder for my Hassy, gave them a quick call explaining my mistake & telling them the one I should have ordered. They were wonderful! They even discounted the eye-level finder (the right one) shipping for me!!!
Not to mention the fact that I bought a "Bargain" graded finder whose glass is absolutely spotless! Dang! :o