I have been using one since December and it has been fairly reliable. Linux support is quite good as is the community they've built. It's also cool that the Embedded Controller firmware is public and they have some community members' threads showing how to customize it as well.
They had some teething issues with power drain from the expansion ports while suspended - an upcoming BIOS update is supposed to fix those. The battery lasts around 6 hours, so if you can live with that I would highly recommend this for your needs.
On maintaining battery life, they have a feature to limit the battery charge level to a customizable limit (usually people like to set this at 80%). Other than this, the fact that this is easily user-replaceable should help.