Never owned RBION, but played it enough to know it's enough stop and go and long ball times to keep me from loving it. But if that's your thing you'll probably appreciate it because there is a lot to like. I've have however owned quite a few pins (60-ish) and Avatar is among my all-time favorites. It's an unusual experience...instead of flowing all over the place it tends to feel like you are fighting the machine, constantly trying to regain control of the ball.

Initially it can be brutally hard and the 3 bank target feels strange and like a flow killer so I think a lot of people play a couple times and walk away thinking it sucks - myself included at first. In fact it's the first game I've ever bought primarily because I began to appreciate the fact that it owned me every time I played. Once you get it going it's so incredibly immersive in a way that reminds me of LOTR (it's nothing like LOTR otherwise).

Rule-wise Iron Man is probably most similar but aside from rules the only thing I feel these two share is the fact that you feel like the pin fights back. I've owned both and feel that Avatar is the far superior game, though I seem to be solidly in the minority on that. In terms of game play I feel like it's somewhat similar to Pinbot and Big Buck Hunter (two other woefully unappreciated pins) and a whole host of older pins where targets mattered more than ramps and the ball isn't conveniently delivered back to a flipper on most shots. I can definitely see why Avatar is thought of as a dog out in the wild, but at home it shines like not many others.