Another vote from me, in some ways i enjoyed this more than Galaxy. Great graphics, some really nice music, excellent controls once you got used to them.
I don't understand people saying it's more linear than the others in the series, they are all relatively linear if you follow all the clues give you. Perhaps the fact that you were clearly directed from one planet to another at times made it feel more obvious.
Along with Naznatips and a few other guys, i never had to go back to collect energy cells, i found all of them just on my playthrough. Perhaps those saying the game was too linear did not use the short leash the game gave you, allowing you to easily find the cells in the first place.