I've been using two K-x bodies for a couple of years now with no issues. I get around 600 (give or take) shots per charge on a set of Kodak or Energizer NiMh batteries, which I'm totally fine with. I don't know if you use live view a lot, but that can be a juice sucker. I rarely use live view, so that could be a factor.
Another thing to consider about the battery issue is this: I don't know what battery charger you're using, but the fast chargers that charge in 15-30 minutes will kill your batteries. If you used to have good battery life and now you don't, that could be the issue. I use a Maha charger that charges in 1 to 2 hours.
Regarding focus calibration, one of my K-x bodies was dead-on when I got it, but the other one needed a bit of tweaking, which was no big deal. It's been right on the money ever since, but every photographer takes the occasional out of focus shot. It's just the way it is.
For what it's worth, I've owned two Q's, two *istDS bodies, a K-100D, and two K-x bodies, and have had great luck with all of them. You can see some of the shots I've gotten with Pentax gear
here.
If I were you, I'd try updating the firmware to the latest version, evaluating your battery situation, and checking the focus calibration. It is also possible you just got a lemon, but that can happen with any brand of camera. If nothing else, you could just pick up another K-x body (or other Pentax body) on the cheap here in the forum & keep shooting. I've seen *istDS & K100D bodies for around $100, and another K-x should go for around $200.
Also in my opinion, the build quality, ergonomics and bang for your buck is MUCH better with Pentax than Canon. I had one of the better Canon point & shoots which had a faulty sensor for which they issued a factory recall. After the sensor went bad, I called Canon and was told they would not honor the factory recall, because it expired two days earlier, and I was out $400. That experience, coupled with the generally cheesy build of some of their cameras, kind of soured me on Canon. If you really want to switch, I'd go with Nikon.
Good luck,
Bob :-)