Probably Mass Effect's universe, especially if I consider only that of the original, rather than including any of the content within that universe from the sequels, with perhaps the exception of Omega which I really liked and believed it to be very fitting (mostly due for it being the lawless pit of the Terminus Systems).
If not, probably Dragon Age's and I wouldn't include Kirkwall (I would include some of the characters such as Varric, but not the city itself, there's nothing about or within Kirkwall as a city that spells or rings "Dragon Age" to me, just feels like "a city" and that's about it). But if I had to choose yeah I'd go with Mass Effect. In ME's case it's not just about the characters but also the locales, planets, rich codex, etc. Although arguably Dragon Age has a more detailed and fleshed out codex than even Mass Effect's (the original I mean), difference being that there's less species/racial variety in Dragon Age than in ME, and what makes Dragon Age special is more the characters themselves and their own stories rather than the "whole thing", in my opinion.
But ultimately both ME and DA are just plain awesome universes, one is fantasy the other is science-fiction, so it's a matter of preferences, and I have a personal preference towards science-fiction most of the time. Also I adore the Warhammer 40,000 universe, but I've known about that one from many years ago thanks to the table-top games I played back then so I rarely include that universe within the "video games" domain, rather I mention it when I can just go "overall" (literature, movies, games, etc, then I pick up WH40K).