I would do this in a minute, and you're talking about my home airports. SNA is by far the best option for Orange County, if that's your eventual destination (but good luck getting CO award seats; they're very stingy with SNA), but ONT is actually quicker to get to and FAR easier to deal with than LAX (and award seats to ONT are fairly easy to snag on CO). The only real downside is ONT doesn't have any lounges no matter what credentials you might have (SNA has UA and AA, and LAX has them all).

Not that it's relevant in your situation, but I get almost two hours more sleep when departing ONT rather than LAX, and they're equidistant from my house, so that gives you an idea of the difference in parking and check-in headaches.