Played through them all and I must say that they have only gotten better with each game.

The first Metroid Prime had excellent graphics but at least for me the step from 2D to 3D wasn't done very well back then. Lots of searching through ruins, few fights. Not my thing - at first. I got constantly lost in the 3D world too and had to use several maps from internet sources to find my way around.

The only real handicap of the Prime series is that while the older Metroid games were mainly action based with hordes of enemies waiting around every corner there is nothing like this to be seen in any of the Prime games. But you should get used to it quickly.

So while I didn't have that much fun with Prime 1 I really enjoyed Prime 2 and 3, the latter being particularly great. The Prime games have more of a story than the previous games as well which isn't a bad thing. The music cannot compare to Super Metroid but it's good enough.