Some of us use ExpoDev on a Palm device. One of the possible problems with a Palm can be battery failure. Other things can go wrong as well.
When my Palm battery started to fail I purchased a Handspring Visor to use with ExpoDev. The Handspring can be used with a very convenient tape back up in the field, while the Palm can only be backed up via Hot Sync. However, I felt that the Palm had a better screen, and was a bit easier to use.
For those interested, I have located an excellent source of service for a Palm device. Christ Short has many positive reviews, and his service appears to be excellent. My battery has been replaced, and a general evaluation of the unit was performed.