The Commanders are great airplanes. I have over 1500hrs in them. The -10T is hard to beat! 5400hr TBO, no phase inspections, and they sip fuel (250 lbs/hr aside at 270). The -10s allow you to hold your HP to a higher altitude than the -5s did. It is not uncommon to hold a 2000ft/min climb up to FL220 (in the summer), after that it drops to about 1500. OUTSTANDING single engine performance too! With full fuel, and a pilot you can still load close to 1000lbs. 290-300TAS is common.
The Meggit system is nice, expensive but nice. The good thing about it is that it is RVSM comp. The plane also has excellent short field performance.
The only bad thing about the plane I can think of is the fuel system (on the 690 series). The fuel tanks are all interlocking so it does take awhile to fuel. And the rubber fuel bladders are a drag when maint. has to be done in the wings.
If I had the money that is the one I would buy!