Certified Commercial Appraiser Needed in Columbus, OH!!

This is a 2 part post, first off, I am in the process of offering on a multifamily property in Columbus and am at the point where I need an appraisal done. I would like some feedback on anyone experience, good or bad, with certified commercial appraiser in Columbus. I have a couple names but would like as many options as possible, any help would be greatly appreciated.

Secondly, what types of questions should I be asking an appraiser prior to making a decision on hiring one?

As always, thanks everyone for your help and participation!!