Assuming you get Prime, which you should, get a NON player's choice version or whatever they're called. There's lots of sequence breaking opportunities. If you only like to play through a game once, then it doesn't really matter what version you get.
You can't unlock the hardest versions in the Prime games until you complete it once on normal. Besides, you don't want to play on hard for your first time. Especially not against...him. Chad knows. Chad, did you ever beat OP? (Initials should be safe from spoilers.)
The Prime series is one of the best in recent history, IMO. Easily. I've played them all around 3-5 times each at least, so far.