make sure it's a renaissanced commander... people that have any experience with twin commanders will know what I'm referring to... they're still under the 1million mark, but WAY fewer problems because essentially what they do is go through and gut it and upgrade and replace everything.
A good good friend of mine flies a commander and they like it well enough, but dealing with all of the failures and such (especially with the electrical system- generators, GCUs, etc...) they would of been better off buying a Citation II. Old commanders are notorious for these kinds of problems, and that's where this whole "renaissanced" commander comes from.
Also, make sure you do your homework for maint. Find a good mech who has experience with commanders and garrett engines (assuming the Dash 10 conversion here.. which is almost a no brainer). Some guys wont touch them.
If you can do all of that, the commander is a good, cheap option for the endurance and usefull load.
Let me know if you need any more information, I can try to answer from my own knowledge or pass any questions you have along to him.
I've flown the Conquest II, there's an operator next door to me at the airport here who uses it. But that sounds like it might be out of your price range.
IF you could swing the 1.4 million though, certainly worth taking a look at over the commander. Cessna is a good company.
-James