For reliability, I'd put my money on Toyota.
Generally I'd agree with you. The Focus has bucked Ford's low-reliability trend, although that probably has to do with Opel and Mazda engineers working on the platform (they don't advertise it, but the Mazda 3 and Ford Focus and Opel something-or-other all share a platform). So when thinking about a Focus versus a Corolla, the reliability's not as far apart as you'd think.
In fact, if Consumer Reports is to be believed, most of Ford's products are average or better in reliability these days (source:
http://www.wheels.ca/article/32205). Then again, some people think Consumer Reports is a biased publication that doesn't properly publish its test data:
http://www.allpar.com/cr.html.
No matter what brand you buy, though, even the highest-rated have an average of 1.01 major problems per car every 10 years (wish I could find that article back, it was eye-opening).
For cost of maintenance (if something breaks what would be the parts + labour), I would say Ford would be cheaper. But how many times you are in the shop for repairs, I think Toyota would be less.
Toyota parts for the Corolla are mostly made in the US these days. Ford and Toyota parts aren't necessarily far apart in cost, because a major component of parts cost is the cost of shipping it from far away (like Bimmer parts from Germany, or Mitsu parts from Japan).
For longevity, well going with track records, I'd have to say Toyota again.
If we were comparing Focuses and Corollas, I'd agree with you. But we were comparing Focuses and Priuses, and Priuses have had some problems that Toyota has been quick to fix as part of "regular maintenance". And to be honest, the kind of person who buys a Prius is probably more conscientious and probably maintains their vehicle better than average. And that has a lot of influence on the lifespan of the vehicle.
