If TIG is what you really want, the reason you're buying a welder to start with, then I'd urge you to opt for as good a TIG welder as you can afford/see the need for, not a "watered down" version.
I use mine frequently and really appreciate having a machine that can do more than I can, and as I learn more the machine is ready with more features and options I can use. I'd be frustrated if the machine were holding me back.
Only occasionally do I wish I had a MIG welder, and I'm sure one day I'll get one, but with a good TIG welder already in the shop a MIG is not high on my list.
Grigg