Well if I was going to go with my own review, I do respect people's hard work and I know people put their hearts and soul into these games, but Alpha Protocol is too much looks like a metal gear solid clone to me, and there's so many console games out there like it, I could see why it didn't get a good review. I'm sure it has a different story unique features but third person shooters like that were crazy innovated when ps1 came out, since then there's been so many special forces third person view games released that it just cliche.
Metal Gear Solod
Siphon Filter
Duke Nukem
Prince of Pursia (???)
Those are just a few games off the top of my head that are like Alpha Protocol. From my opinion I think reviewers are looking for something new, innovated and something that hasn't been done before, you play one 3rd person shooter game you've played them all.
To be fair, Alpha Protocol is a "3rd person shooter" in pretty much the same way Fallout 3 was. (Well, I played F3 in third-person mode, at least - but otherwise we could say Alpha Protocol is a "3rd person shooter" in the same way that Fallout 3 was a "first-person shooter.")
Personally, I'm not too worried about what score any of these games get on review sites. Occasionally, they're useful for a game I'm undecided about buying - but once I've already purchased the game, it's all kind of irrelevant. I already know I'm going to be buying New Vegas, and I already have Fallout 3 and Alpha Protocol. It's not like I'm going to earn more Gamerscore or something if the games I'm playing all have "scores" within the range that I feel appropriate. I mean, I know what I'd probably score these if I were a reviewer, but I don't even know what either games was rated by any of the reviewers I trust.
Plus, it's not like there's some inherent metric involved in a reviewer rating a game. They're not going to take x amount of "points" out of a review for every bug - it's usually more to do with to what extent any existing bugs diminish their experience of playing the game. For example, a game can get 5 stars or a 10/10 and still have bugs, even if it's not an absolutely perfect game.
Anyway, back to the point. If I start seeing a ton of really detrimental bugs, or excessive lack of polish, in Alpha Protocol, I guess I might be a bit more worried about New Vegas. But personally, my mind was already made up about NV. I'm going to be buying it either way. Plus, AP is a new IP they've built from the ground up, and with NV they're using (what I'm assuming is a separate team, in the first place,) an existing framework upon which to build the game. Fallout 3 ran just fine on my rig - I'm expecting the same rare non-fatal error here and there that I had then, but overall I'd bet that it's going to be the same experience in terms of technical quality.