I just logged on to Geico's web site to get a quote for our two "daily drivers." We live in Connecticut and without going into detail about the cars we own, here's what I did: First I logged on to USAA's site and printed out a copy of my automobile policy, which includes both cars. Then I built a "custom quote" on Geico's site, using the exact same coverages, benefits, and liabilities that I have with USAA. Needless to say, Geico was less expensive. My USAA auto bill is $1992.32 a year. For the exact same coverage through Geico, I'd pay $1493.64, for a difference of $498.68.
So on the surface it appears that going with Geico would save me about $42 a month. That's enough for one Friday night visit to our favorite pizza place. However, every year for the past 42 years, USAA has sent me a check, usually somewhere between $600 and $1000, in November or December and as well puts additional money into our "account", which eventually I'll withdraw, after leaving USAA. I think I'd be foolish to switch insurers. Truth be told, I wasn't going to switch anyway, regardless of the outcome of the comparison, but I did want to see if there was any real savings to be had, and for me, there just wasn't. YMMV, obviously.