Not to step on anybodies toes, because I surely don't know about the small companies like KSI, Diamond, etc., but I think you would be far better off technical support wise by buying a used Citizen, Tsugami, Star, or Tornos. Especially if it is going to be your first swiss and you are buying it used. Parts for most will be readily available. But it's the helping hand for programming, parameters, and troubleshooting that will make all the difference in getting parts up and running or paying for a large boat anchor because you don't know how to use it!
Good luck in your decision.