Like others said, going for both classes is a pretty good idea. Voy + Champ combo is great for leveling and you can work on one char at a time. Generally, champ doesn't require a lot of work to be a pure tank and even if it's just that, it's still good to help your voy in leveling and what not.
Voy, on the other hand, requires a fair investment (CA Gear, Gems) to be decent. Of course, after a certain while, focusing on champ and making him more than a Meat Shield is probably a good idea as well (Champs are beasts when gemmed and properly geared).