To me, ME1 is a legend of world building. The combat was a touch janky, but the storyline was great and the attention to narrative detail was excellent. If you're a sci-fi nerd, that codex though....
ME2 is a legend of character building, that took ME1 and flipped it on its head in a wonderful way. It was a strange story line overall, but the characters drove it forward, building on that base ME1 had built. Combat was streamlined and RPG elements were removed, but it had polish.
ME3 combined the best elements of the previous installments and took that on a rollercoaster, and I loved it. The ending killed ME3 for a lot of people, but what a ride getting there.
ME Andromeda was....okay. It was okay.
Just an incredible series that ranks up there with my favourites of all time in any form of media. Even polishing it up for modern systems has me more excited than most upcoming games.
Alright, I'll stop fanboying it up now.