You've already had a taste of welding, and apparently you liked it. At this point, I'd guess you're not going to quit welding. Save your money, buy a quality machine that's oversized for what you need. (200amp @50%duty cycle) Then you'll be able to use it for the next 20 years. Yes, it's more money to pay now, but the $ per year works out better in the long run.
Miller, Lincoln, Esab, and maybe Hobart would be the only brands I'd consider.
I don't have any experience in the multi-process machines, so I can't make any recommendations there.
Also if you decide to quit welding for some reason, the name brands will hold a better resale value. Not that I'd ever encourage someone to sell tools. Blasphemy!