I've reads that Nu tool welder parts are difficult to obtain, and that the welders don't last long under regular use.
So go cautiously until a few more people have posted on here and given more informed opinions.
I had nothing but problems with my nu-mig135 and couldn't really find any spares or information on it, nor any other owners that had had anything but problems. I would get a welder that's well supported by spares at the very least. Would not risk a nu-mig personally, I let mine go for 41 quid on eBay a few weeks ago.