Obsidian is basically BIS post-Fallout. It lacks almost all the key people who worked on the original Fallout: Tim Cain, Leonard Boyarsky, etc., who went to Troika. But it has a lot of the key people who worked on or were responsible for PST and IWD: Chris Avellone, Dennis Presnell, Chris Parker, Josh Sawyer, Feargus, etc. I think Obsidian lost Dave Maldonado (responsible for the Brothel and Clerk's Ward in PST, among other things) a while back to Blizzard, which is a shame, and they also lost Colin McComb (Trias & Fhjull, Foundry, & other design work), but they recruited George Ziets, who seems to be a top-notch lead. In terms of artists and musicians they lost people like Eric Campanella (PST monsters) and Mark Morgan (PST soundtrack), but their new team does a reasonably good job, if not spectacular.
Post-Fallout BIS and Obsidian are quite similar in many other ways, including a reliance on third party engines (PST and IWD were both IE games), a balance between story-based and combat-centric titles, the latter of which typically isn't as good (but I guess IWD fans will disagree), a genuine attempt at C&C in most of their story-centric RPGs, and a tendency to release games that are unbalanced and/or unfinished. In any case if you're one of those people who worship Chris Avellone for PST, then you should be able to see his touch in most of the Obsidian games. But that's a topic for another post.
As far as luster goes, I don't think Obsidian ever had that much luster. Even in the BIS days, after Tim Cain and co. left, the only game they made that could truly be considered a classic is PST. In fact, it is because of PST and Chris Avellone that Obsidian gets much street cred from fans. In some ways, everybody's basically just waiting for the next PST (perhaps in vain), and hoping that Obsidian lasts long enough to make it.
