It is their best game, and a pretty good one at that. But nothing they did after that comes close. And games like PoE and TOW get some of their recognition more from being made by Obisidan than on their own merits. OK games, but nothing special. No offense, but Obsidian is somewhat overrated and their later games are doing nothing that devs like inExile, Owlcat Games, and others haven't done or are doing too (and sometimes better than Obsidian and with comparable budgets).
Obsidian has been basically working on autopilot, without any effort to push the envelope. The Pathfinder games from Owlcat Games are more ambitious than anything Obsidian did since NV. And now that they are an "AAA" studio (in their own words and MS's), they're starting to sweat and come up with excuses on why their future games should not be compared to BG3 (and I don't mean graphics and cinematics). Expect Avowed to be a good game, but don't expect anything that will blow your socks off. It will probably be little more than The Outer Worlds: Fantasy Edition.
But I'll be glad to be wrong if Avowed proves that Obsidian still has any life left in them to contribute to pushing the RPG genre forward.