My vote's for the upcoming Accent, if you can wait... here's why:
1) Although Hyundai and Kia have "equivalent" models built on the same platforms: i.e. Sonata-Magentis, Elantra-Spectra, Tucson-Sportage... the general rule of thumb (according to one Korean auto magazine) is that the Hyundai is generally built to a higher spec (i.e. better quality control), and would warrant a slightly higher price... This was very evident to me when I test drove back-to-back the Tucson and the Sportage... It is also evident when you look at Consumer Report reliability ratings.
2) Although Korean cars GENERALLY have weaker resale values, Hyundais CONSISTENTLY tend to yield a higher resale value than the Kia;
3) There are more Hyundai dealerships than Kia dealerships in Canada, if you move and need to find a dealership, it is more likely that you will find a Hyundai dealership;
4) There will most likely be more Accents on the road than Rios, while this should not be an immediate concern for you today, it may be a concern several years down the road, when you may need to find used parts from wreckers... yes, it is silly to think THAT far in advance, but speaking as someone who used to own a Merkur, it is incredible how relevant this factor is, when your car is 10+ years old, and the dealership refuses to order an obscure part and your only option is the junkyard... I will venture to guess that a used fender for example, would be easier to find for an Accent than a Rio; and
5) The NEW Accent looks better! (IMHO)!
Cheers,
Infinitime