Storywise - the trilogy is still one of the best sci-fi stories told on the console. Gameplay - a bit clunky especially on 1. However, even 1 is perfectly serviceable ... except for Mako :).
The gameplay of ME2 and 3 have aged terrifically, ME1 also holds up well just because of its story.
Mass effect holds up MUCH better. The shooting mechanics are clunky on the first game but the storytelling and world building is unmatched. The combat is streamlined in 2 and 3 and holds up well in my opinion.
Probably going to be a mix. Combat wise Mass Effect 1 was always clunky and a bit hard to get into. Mass Effect 2 and 3 turned it into a more standard 3rd person cover shooter (with 3 refining it to the point that it was actually quite fun). Also hysterically from you citing Kotor, I think you are gonna love this series. This is the game Bioware started working on after they shipped kotor. You can see the influence very clearly if you look at Mass Effect 1 closely.
WOW, ME fans are a passionate bunch. Thanks for the responses. I guess I'll be checking this out.I'm saying this as someone who would tell you to play them even without a remaster existing...
They are VERY good, but also very different. Lore and story is superb. Mass Effect 1 is the most "different" in gameplay because while ME2 and ME3 are far more familiar to fans of cover-based shooters, ME1 is more stat and RPG focused and thus is a bit "clunkier" in execution. It also has wonky vehicle sections, but also the most exploration of any of the games in the series with vast, open planets to traverse. It's still fully playable, and rumors are they're tweaking ME1 to be more in-line with its sequels.
I would call them timelessly good, but the reason we're so excited for a remaster is there's a lot that CAN be done with them. I don't expect every flaw to be polished out, but even as-is it's an incredible trilogy.