I've tried all of the major applications. By far, Runkeeper is the most feature-complete and most routinely updated. If you're going to buy an app, why not buy the one that's being consistently improved, features added, community support, etc.

Also, if you're desperate to keep the battery going, disable the phone, wifi, and even data. It'll last quite a while. Just re-enable the data when you get home and click "re-upload my route."