Ok, my Motorola/Verizon Droid was able to do what my Apple/ATT iPad cannot: show me the Cannondale wb site. I'd say these two bikes are well suited to your use as you have described it in a later post. We do go on about tires but they can be changed at little cost. Either one has tires that should keep up with your boys, at least until you determine what would work better, and possibly till they wear out. I'd lean towards the Ultra because the fork description makes me think it is 80 mm instead of 50 mm travel. Hard to say for sure since these seem to be Cannondale's in house designs. Ask the dealer, he should have something intelligent to say about this. If you are going to get a suspension fork, and you may well need one because of the boys, you want the best one you can get. Hybrid forks are light duty, if you want a manly fork you'd have to go to a 29er. It sounds like a light duty fork would do for you.

Cannondale describes these models as a hybrid between cross bikes and 29ers and I think that makes them close to ideal for what you want. The rims on them should fit good 28 mm road tires later on if you want to do that and the lock out forks will only be a small weight penalty for road riding. The Quick CX Rigid was on my short list but my dealer sold Fujis. Naturally he now sells both....

Ken