If you're going to ferry elderly folks around the Teana for the win. They'll like the rear legroom.
For after sales service, both TC and UMW are more or less the same. Some have bad reputation (certain centers) and there are others that work quite well. But like what 6uest said - it's probably easy to find out which one has the nearest (large) service center nearest to you then go from there. Don't go to those small service centers, the big ones generally have better rapport.
Since you're buying new, I'd suggest you consider either the Camry Hybrid or the Teana. Both are quite good to drive around but Teana is more superior in space. Toyota has better resale.
Problems wise, the Teana is the 3rd or 4th generation one now, so it has considerably less problems compared to the older generation ones. The latest one has a CVT gearbox cooler, larger calipers and generally the engine is bulletproof for the average driver. I personally drive a Nissan Sylphy and problems wise hasn't been much except for the usual wear and tear. Invest in good oils (or whatever the center gives) and invest in good brake pads and the car's a good drive around town. Quiet engine, quiet gearbox and it has the Nissan quality.
Toyota Camry on the other hand is more of a new model, new interior, new engine, everything new. Hybrid one even more so. However it's a Toyota so you'll probably won't have any issues with reliability except for the recent recall on the power windows.
Both cars are generally quite good. Camry Hybrid probably will have better fuel consumption around town driving but highway I suspect the Teana will be better.
One is new tech and the other is been-there-done-that tech.
Both are priced around the same. There is one disadvantage the Toyota has over the Teana - Camrys are hot theft material. Invest in a good aftermarket alarm if you go for a Camry.