I've used both auto and manual, now my only manual is a pass-through at work. Both types work fine, the 808 is a good battery, and reliability is fairly good (there are some early life failures, it seems, with everyone's batteries -- it just plain happens, including with manual batteries; if the battery is good after a couple weeks, it seems like it's then going to be good long term).
For driving or other hands-needed activities the auto is super. In a car I use an auto pass-through -- no drain on PV batteries, and the extra voltage gives an even better kick than the standard 808 3.7V output.
With an auto you want to use clean cartos -- blow out any excess juice, wipe the threading before attaching them. Keep the air inlet holes clean, and swab with a qtip and alcohol every so often to get any gunk starting to build up in the connector. Pretty painless, pretty low maintenance.