I agree with both of you, but for different reasons.
I think the Accent will be a better car, especially where MPGs (highway) are counted. I know that Accent will sell in crazy numbers, and work tirelessly for thousands of U.S. drivers. However, subjective as it is...I cannot get into the Accent's styling, and on a more personal note, I can't trust Hyundais yet.
Namely, the depreciation curve is very harsh. If/when I go to sell my car (Yaris/Accent/Fiesta/etc.), I want to recoup as much of my money as possible. I cannot do that with the Accent. Plus, I am not feeling the "styling" of that car. The Yaris is more clean and restrained. Call it vanilla, call it what you want.
But I like it. Especially the triangular tail lamps and the rake of the rear hatch and rear sideglass/B-pillar profile on the 3-door. Looks purposeful, yet still elegant. Again, subjective as all hell, but that's what makes us human, and why we all don't just drive minivans and be done with it.
Finally, I'll admit I'm kind of a badge snob. Toyota earned their pedigree decades ago, now they feast on it (not as much these days now that they have been slacking). Hyundai still has a few thousand calories to burn, a few more sportscars to build before I'll give them a shot. But for now, in my biased eyes, Toyota is the "safe" choice. If I flew by the seat of my pants, I'd get a Chevy (Daewoo) Sonic with the turbo and 6-speed and just call it a day. But we all know those won't last as long as the Yaris...or the Accent. But god, what fun that Sonic must be to drive before it falls apart the day the warranty expires!
Having sat in (not driven!) the new Accent, I'd rather keep my Geo. No, that wasn't a joke. I could not imagine willingly paying thousands for that car. I'd rather have no payment and drive the Metro into the ground.
The Yaris? That little car excites the hell out of me. I love the way it looks (inside and out), the way it drives, and it's optimistic little personality. It's little mono-wiper thing.
It's little uncluttered 3-spoke steering wheel. I don't know why, but perhaps I was just the customer (early 30s, first new car, male, soon-to-be-professional) Akio Toyoda had this restyle done for.
You just know Toyota is losing money on each one they sell in the U.S.