I've been using a CatEye Stealth 50 GPS device to record some of my longer rides. I've not been using it for commuting though because my commute is only ~30 minutes, and the CatEye takes 3-5 minutes to start recording data. I don't want to add 10% to my commute time just for GPS lock :)*
Would upgrading to one of the Garmin devices like an Edge 500/510/800/810 make a significant difference in initial lock time? (I'm somewhat spoiled by my cell phone and car that achieve locks almost instantly)
* That said, the CatEye was only $150, and at that price I couldn't be happier with its performance.