Don't sweat it, Semper Fi. Both bikes are quite nice. Both will give you the more upright geometry of a mountain bike without the mountain bike weight and useless(for the road) suspension. The Sirrus is set up more for the road while the Trek is more capable of handling dirt roads, fire trails, and rougher roads due to the wider tires and slightly lower gearing. But since there's room for fenders on the Sirrus(and the Trek), you can easily put on some wider tires for those trail rides. Likewise, if you got the Trek and wanted higher gearing, changing the cassette is not that expensive.

So, either way you go it's cool.