The bike looks pretty good component wise. The seat looks like it might be a little uncomfortable, but that's personal preference. It'll definitely fit your needs! Jamis is a good bike brand and is priced well. If you don't have any biking stuff, make sure to pick up a helmet! You can ask if they give a discount on accessories when you buy the bike so you can pick up that, a bottle, a pump if you need one, and maybe a pair of lights if you plan on commuting at night. Also, some shops will give free tune-ups which is pretty nice, so be sure to ask them if they have anything like that. A well maintained bike will always work/feel good! Anyways, the rim breaks should be fine for Portland, but just make sure to ride cautiously in wet conditions! If you have any issues braking, you can do things like swap tires although I think those tires look fine. Have fun!
Also, this is the bike lock I use:
http://www.amazon.com/Kryptonite-Krypto ... +bike+lock