I have owned The PowerTig 185 and now own the 200DX both are great machines and will do a wide variety of welding jobs, My first Everlast machine was the 185 which was tig only or i would probably still have it. I moved up to the 200DX to retire my old miller stick welder and gain the pulse function on the 200DX. Both are good machines and you will get a lot of support from forum members on suggestions and settings for the machines. With your background you should be just fine with either machine and will get to enter the field of aluminum welding with its little quirks and picky settings. Aluminum is like painting a show car clean clean clean and everything will be just fine.

Good Luck on your Decision