I love the story, and the universe, and there are some aspects of it that I really think are even superior to Star Trek. And for me being pretty much raised with Kirk, Picard, and the others as proxy babysitters, that's saying a lot.
I feel similarly, I adore the ME universe. Even with all the annoyances in ME1, I loved the game because of the universe it took place in. I've waited my whole life for a Star Trek game that truly managed to capture what makes that franchise so special to me, and the only games that came close in all that time were the Mass Effect series. And don't even get me started on how much I love the characters, let's just say that if Garrus were a real person I would finally join Facebook just to friend him. And from that perspective, ME3 is a triumph. There are some absolutely wonderful moments with the main characters, some which may even bring you to tears, and you get to visit the homeworlds of almost all the major races. The decisions you make through most of the game are huge, the fates of entire civilisations are in your hands.
Just be aware that the ending is so poorly received among fans that the final enemy in the game, a lowly marauder, is considered a hero by the fanbase because he tried to prevent us from getting to the ending. Never forget Marauder Shields
, we should have heeded his warning.