Just as Jim has said they are great. I got myself a 250 a few weeks ago and am massivly impressed. Really does compliment my welding. Might be worth ringing rtech and ask if the have any agents/ distributors local to you. I managed to get mine cheaper through a local agent and also have the backup there I can call into they're shop if I have any issues.
I have one, really good machine for the money. Good duty cycle and a lot smoother than a hobby machine, but not as smooth as top end machine e.g. a Kemppi.