Most bikes at a given price point are very similar in terms of specifications. The Sirrus has higher stock gearing. The Trek is a bit lower. If you're in a flat area, this means the Trek might feel a bit slower. In a hilly area or carrying a lot of stuff on the bike, the Sirrus would feel slower. Gearing can be changed after you buy a bike, so it's not a huge deal. And as you get stronger you might find you want different gearing (and that doesn't always mean higher... I'm a much stronger rider than I was a year ago, which means I'm carrying heavier loads, hunting for steep hills and want good low gears)

I'd make the decision based on which bike is most comfortable. A good fit means you'll ride more and longer, so you'll get more out of the bike.

Make sure you've got room in your budget for extras. Often extras work to eliminate the "what if" barrier. What if it rains, what if someone tries to steal my bike, what if I'm out late... Locks, fenders, racks, lights, helmet... all of those can be useful. Even if you don't plan to ride at night, lights can be helpful. They make it easier for people to see you in rain or fog. Fenders do the same kind of thing. If a skunk stripe on your clothes will keep you from riding, fenders are a must.