With the Nashbar you save a small fortune in the cost of panniers, and since it's a commute the distance traveled is quite a bit less than touring thus the Nashbar pannier will last quite a long time. I have the Ortliebs for touring but I don't use them for commuting mostly because I don't need the bulky bag since I don't carry a lot, so instead I got a Garneau briefcase pannier on sale for $14 from $45.