The main problem with OAK is cost of living- it's not easy to live in the Bay Area on $30k if you don't already have a place. It's not the ACP- from my experience, he's a pretty good guy. Weatherwise, it's no worse than up north, and often not as bad. The other main downside to OAK is slow upgrade time- I know there's not much in the way of 99 runs, and what few there are stay senior. However, it's possible to overcome this by bidding on outstations at other bases...
And some people DEFINITELY make more than $28k a year- there are several runs that pay more than 8 units per day. It's a matter of being able to bid them/having the will to fly long runs day after day.