I started off with the Daytona Gun M4 (G&P WOC), and went over the Polar Star (VFC SR635), and ended with the Tippmann during their initial release.
In the end I reverted back to GBBR
Simply cannot bother with re-filling, and carrying around the hose and tank X_X; the idea and concept is cool and fun, but there's a reason why I quit paintball in 2005.
If I ever went HPA again I would only consider:
1) P* with HPA stock
2) Daytona Gun LMG (M60)
Don't get me wrong, they are cool, but for indoors I find the hose to snag on the ply wood, and annoying to alter left and right hand when shouldering... rather just be free and deal with propane.