Both ME & ME2 had their ups and downs.

ME was terrible for the equipment/inventory system. Basically the UI was utter crap. Everything else was pretty good if not great, although the Mako exploring could have been improved. It just needed a bit more thought to the presentation of the planets, I felt.

ME2 was terrible for the scanning system. Basically the way you made money (or 'resources') was utter crap. Everything else was pretty good if not great, although the battle areas could have been more varied. It just needed a bit more thought to the variation of the battlefields, I felt.

For the ME battle areas, I think it was a bit better in that it had more opportunity to do different things, such as that one area where you drove the Mako around a sort of obstacle course planet, shooting bots and turrets and whatnot, and then nearer the end you have to hop out and start sniping over a vast distance before you would charge in. There wasn't anything remotely like that in ME2. Overall I really enjoyed both games, though, despite the parts that could have been done better.