Best lore and best lore integration are two different things, and there seems to be a fair bit of people talking past each other on that front. As to the question in the title, obviously there's also a subjective aspect to what best lore integration means, as to some that may mean ~environmental storytelling~ (in particular, 0451s fall in this bucket) or From's style of "item descriptions as lore" approach to worldbuilding, because it's lore delivered as a result of player-initiated gameplay. But ME1 and DA:O (i.e., Bioware at a particular stage) both do a very good job of worldbuilding via the main narrative and pure character dialogue (as opposed to other avenues, since reading the codex is completely optional), which in my mind is better "integrated" in that it is worldbuilding that happens without the player going out of their way to find it. YMMV, I guess.