I've been on both sides of the BigCo fence, and in my experience, the small companies I've worked at have been much more dysfunctional than the alternatives. A BigCo is usually a loose conglomerate of smaller fiefdoms; -much- the sanity level in your team depends on your immediate boss and coworkers. If you luck out and find the right bunch, you're set. A small company is usually a larger fiefdom than a BigCo team, and self-selects for certain bodily orifices, doormats and complexity junkies.

YMMV.