Tig welders - discuss

I have played a little with a TiG a friend had - but it was on valve covers (steel ones) and I was just working on the "everything at once"...lol. I found it difficult, but lots of things are difficult when you first start...lol. The 907627 can do aluminum, but it doesn't have the finers adjustments of the next model up. It's a hob by model - the next step up is professional stuff that is another grand more $$. I don't mind spending for results but I have no point of reference yet... My plans include chromoly chassis, various misc aluminum stuff, and stainless steel for headers and turbo manifolding. I know some guys like TiG for everything - I like Mig for steel and bodywork.