Great Planes !!!!!
I have flown the 500Bs, 500S', and a turbocharged 500B (aftermarket kit that gives more headaches than it is worth, maybe a 20-30 kt gain is all ). The big difference is that the 500S' went to the 690 style spar treatment with the stainless steel strap under the spar (disimilar metals), this could produce corrosion that the 500B doesn't seem to have. The 500B also has a better useful load, by about 300-400 lbs. The Shrikes were typically outfitted with heavier interiors, more avionics, and the nose was heavier, still a great plane to fly. Don't shy away from the hydraulic nosewheel steering, all Commander pilots get use to it and it is a no big deal issue after a few flights. You get nosewheel steering with the first quarter depression/travel on the rudder pedals and then the brakes come in, you can always tell a new Commander pilot by the way he or she is jerking all over the ramp.
Do a thorough AD and SB search along with a quality Pre-Buy inspection - read annual inspection - as many outfits don't give a guarantee with an ordinary pre-buy. The spar inspection intervals can vary depending "if" anything was found in the way of corosion. Stay clear of anything that shows corrosion in the wing spar. Obviously engines with quality overhaul history are a must otherwise the full (1600 hrs ?) TBO is optimistic at best. Great systems, handling characteristics, and short field performance. As far as cost per hour, figure $250-300 per hour depending how much you fly it, the big variation is dependent on how the plane was maintained before you buy it. If the avionics have been upgraded to say King Silvercrown and newer indicators, this should reduce your avionics costs. How important is the autopilot to you ? The older A/Ps are pretty much worthless and it is hard to find anyone that can work on them, a lot of the older planes have been updated with S-Tec A/Ps. Also the engine overhauls run around 20K last time I was checking into them. Fuel costs factor into it too, Avgas has gotten rediculous these days. The plane holds 156 gallons as I recall. It has been a while, I do miss them. I hope to own one some day myself if the airline business ever gets off it's ass.
They are a bit pricey due to the limited supply and the overall usefulness. Some of the other 500 series are interesting like the 560, more HP (360 ???) however you need to find someone that knows what they are doing when they work on them. Give Ken Molczan a call at Aero Air in Portland Oregon, a Commander Service Center (800-448-2376) and ask him specific questions, Ken has been with Aero Air for the last 30 years and has been in the service dept. all along. They could also help you locate one possibly.
Good luck to you ! Tell him Jeff sent you.