Upgrade from a Norco Yorkville?
 

My main mode of transportation has been my Norco Yorkville (2013 model). I use it to get just about everywhere, as well as for exercise on days I don't travel. My typical commute is about 7 miles one way.

This last week my wonderful bike was stolen right out of my garage (the one place I don't lock it down with a kryptonite lock). So now I can either replace it with the same thing or take this unfortunate circumstance as an opportunity to upgrade a bit.

While the Yorkville was a wonderful bike for me, I did completely biff it once on a shortcut over a paved path that had a bunch of loose sand blown over it. The tires slipped right out from under me! I "typically" stay to the roads, but where I live they're not always that great (and I do like to take shortcuts when available).

My local bike shop mostly sells Norco in my price range ($400-$800), and they mentioned a 29" wheeled mountain bike might be a better match for my riding needs. Riding it around the parking lot felt like I was on a cushion of air, but I'm worried about how well it would fare on my normal commute. Will those giant tires and front suspension slow me down substantially or wear my legs down faster? Does anyone have some experience with this?

Around here people will usually tell you 1) you can commute on any bike and 2) among new bikes, hybrids and cross bikes do better commuting than do road or mountain bikes.

Thank you Darth!