As with any car -- without exception -- tell 'em to show you the CARFAX.
After that, research engine problems. I forget which, but certain generations had HORRIBLE engines. They burned oil, and lots of it.
Other generations had problems with door handles which broke off, and other sorts of maladies -- most of which can be overlooked if the engine doesn't burn oil.
Want real answers from real owners? Go to
http://www.truedelta.com/.