Robotron 2084 is not a perfect port but, it is the best port available. And it is a bargain for only 400 points.
People will either love it or hate it. The people who love it probably enjoy the nostalgic aspect most. I was considering buying an original arcade cabinet but I figured I would save $600 if I bought the XBLA version instead.
The game play is very fast & intense. It demands quick reflexes, keen peripheral vision, and undivided attention. I'm glad Midway didn't try to improve it or add anything to the game. I like it just the way it was/is. The sound effects in this game are typical of Williams/Bally, they are some of my favorites
The Xbox Live features are a bonus. The Leaderboard will let you know where you stand against the thousands of people who play it. Even if your not a great player, you can still compete for the weekly high scores. Versus is great because you can meet other Robotron aficionados.
My only complaints are that there are missing sprites sometimes when the grunts are bunched together. And high scores are uploaded only on the default (easiest) settings. I don't think the default settings are as fun as the hardest settings.