Don't get me wrong on this, as I love both of my bikes. Buttttt, If I had to have only one, it would be the Crosstrail, somewhat citified, with fenders, rack, Schwalbe Marathon Supreme 35&40, over the Sirrus. Yeah, the Sirrus is citified too! I like racks and fenders, to make my bikes more "All Condition" riders.
The Crosstrail is just a better do it all bike and more comfortable, whereas the Sirrus is more fun, and easier to ride faster.
I replaced OEM All Condition Armadillo tires, 28mm, 115PSI, on the Sirrus - with Specialized All Condition Armadillo Elite 30mm, 100 PSI, tires because I got a smoking deal one afternoon - but it was a mistake - the OEMs were faster tires, even though the 30s were a touch more comfortable.
If you are lusting after a Sirrus or Vita, you won't go wrong - they are GREAT bikes, and lots of fun to ride.
Buy the best you can afford, you won't be sorry! JUST MAKE SURE YOU CHECK BACK IN TO LET US KNOW WHAT YOU DID!