I picked up a 200DX this past spring, the main purpose IS custom bike work, secondary purpose is I'm setting up a job-shop once I get the machinery up and running. That machine fit the bill for both. I personally hate aluminum on bikes, steel for me thank you, however, I'm not just working on my own bikes.
The added features and capabilities were what got me to go with the 200DX, I figure it should fit for me for a long time. I thought about a 250, but cost/use rationalizing, I figured rather than 250A I could just do a multipass if I had something that heavy to weld 
Just remember, as soon as you decide you'll never need the aluminum capabilities, 50 projects will spring up the moment the UPS tracking number hits your inbox
Trip Bauer
Former USN HT
Everlast 200DX New Model
Hobart Handler 125 MIG
Van Norman #12
Atlas 12" engine lathe
'98 RoadKing - 84 Ironhead - 59 Ironhead