Invert Mini- More reliability and faster shots from that extra $100. The Ion is a good alternative if you are strapped for cash.
Smart Parts Ion
2P Freak Barrel w/ inserts
Evolution 3 "Egg" electric hopper
Crossfire Fiber Wrap 4500psi, 68ci
(Also, electric hopper and a 4500psi, lightweight compressed air tank are always good additions.)
Excellent starting electric marker
Easy cleaning and disassembly
Requires frequent maintenence check-ups
Smart Parts out of business= no warranty and few techs
For 4 years, the Ion has been my marker of choice. I hate to see it go really, with Smart Parts out of the business. Though in the time I've used it, it has served me well. Its accurate, cheap, lightweight, and just well designed. The only reason I'm considering getting a new marker is because Smart Parts techs are few and far between and marker problems are inevitable with electrics. Also, there are better markers out there now for those who want to continue playing paintball.
If you happen to find one that's in still good shape and you want a quality tournament marker that doesn't starve your wallet, get the Ion. You won't regret your decision. One final warning though, if you do decide to get one, make sure that you are in a good relationship with a field or someone who can help you with technical problems if you can't yourself.