OAK has been undone a bit by its own success. The result is that the facilities are undersized relative to the numbers of people using them. The concourses tend to feel rather crowded and noisy, the bathrooms tend to be quite crowded, and in general, it's hard to keep such a busy place as clean as the airlines (and I'm sure the Port of Oakland) would like. That said, the security lines (at least on the Terminal 1 / non-Southwest side) don't seem that long, and seem to move quite quickly. (of course, you can avoid the southwest security experience, if you want, by making the ~1 block long walk down the sidewalk to Terminal 1, then going back to the southwest terminal airside).

A concourse extension will be opening soon for Southwest, which may reduce some of the crowding there, but most of the gates are not designed for Southwest's "stand in line for awhile" approach to waiting for a flight--so probably much of the existing concourse will continue to feel crowded.

SFO, on the other hand, still seems to have reduced traffic compared to its design--the remnants of 9/11 and the dot-com crash--so the terminals don't feel as crowded. And the United terminal, which is now connected to the AA concourse, was recently renovated, and features cafes, a decent bookstore (for an airport), and more. Plus, the BART connection to the City is better. Is it worth 2x as much? Maybe it depends on who is paying. But it's probably a more comfortable experience.

-Hayden