I know that Berkeley allows 4 pgs max. and Dean Tom encourages applicants to take advantage of that, but... at this point, I'm just eager to send out my app & right now, I have a 2-pg PS. I can probably tack on another paragraph about "why Berkeley," but it's pretty much going to stay at 2-2.5 pgs.
Do you think it reflects negatively to submit 2 pgs when 4 is allowed/encouraged? What did you all do? Need your opinions because if the consensus is make it longer (while keeping it substantive, of course), then I'll try harder to do that.
I have no experience with this myself, but I am in a similar situation as you are. As a rule of thumb I would always go with quality before quantity. In fact I remember some deans saying in interviews that they sometimes read excellent statements that are only a page or so long.
So my advice would be, unless you have something good and substantive to add to your PS, I would go with 2 pages instead of just bloating the whole thing.