Since you asked...
I purchased my 2010 "6" in January for 49K. It had 20,500 mi and 10 mth's of warranty left (important to me because this was my 1st BMW and I have heard some horror stories). It has been everything I had hoped for and more! I have not regretted my decision once.
As far as the coupe/vert decision... I got the convertible bug out of my system in college. It was great and I loved it. However, I got the 6 to DRIVE! And drive I do... The thought of flipping a convertible and sliding down the road was not a good trade for open air motoring. Besides, I'm lucky enough to have an MC for that. I would never say one is better than the other, it's strictly what your preference is.
Good luck in your search. If interested, send me a reply and I will forward the dealer I purchased from, to you. They were great to deal with and I would not hesitate to buy from them again. I had to drive about 350 mi to pick the car up is a testament to that.