The Mass Effect™ Legendary Edition includes single-player base content and over 40 DLC from the highly acclaimed Mass Effect, Mass Effect 2, and Mass Effect 3 games, including promo weapons, armors, and packs — remastered and optimized for 4K Ultra HD.
I think waiting between Mass Effect 1 and 2 should be mandatory. It’s extremely jarring to finish the first one, and then immediately start playing 2.
But yeah, you cannot pass up this deal. There’s some decent mods for it too.