Hmm, I had to think about this for a minute, but after consideration, I had to say Paizo gets a 2.5 from me, but I'll be generous and round up to a 3. My reasons:
* Their fluff is decent, if somewhat cliche and vanilla. Nothing exceptional, but occasionally really campy and kinda dumb. Rise of the Runelords AP is a good exmaple of this, as are the last 2 years of Dungeon and Dragon. Nothing really bad, but nothing that stood out as really great either.
* Thier mechanics are average to occasionally very poor. Their stat blocks usually have some fairly obvious errors in them (and I'm not a statblock checker kind of guy), and they tend to design adventures for a very over-the-top power level. Paizo suffers very bady from "slap another template on it" monster syndrome, which I find a rather lazy way to add variety to adventures.
* I'm very leery of Pathfinder RPG. From reading Pathfinder Alpha, I don't think the folks at Paizo have a very good grasp of the problems inherent in the 3.x system. In fact, Pathfinder works to make the existing problems WORSE in many cases- and yes, I've played the Alpha rules as a player 4 times- I couldn't imagine trying to run it as a DM.
* From what I've seen and heard, their customer service is good, and whenever Erik Mona posts on these boards, he seems like a really nice, cool guy. Paizo also seems to listen to their fans fairly well, although I find most of the tastes of the Paizo staff not to my liking.
* One big negative is not necessarily from Paizo themselves, but from their fanboys. Wow, I thought some of the 4E fanboys could be elitist, confrontataional, and emotionally twitchy- they are nothing compared to some of the venom and vitriol I've looked at on the Paizo boards over the last 2 years, but especially since 4E came out. Those are the kind of people Paizo SHOULD NOT listen to if they want to keep any credibility. Again, not Paizo's fault, but hopefully the whackjobs have little influence with them, for the long-term sake of their company.