The interface is clunky as hell, like they haven't updated it since 1995, but they're waterproof and AAs are brilliant as you can just buy them in a petrol station or wherever and never get lost. There is a bar mount, which is like a few quid on eBay.
Also, what's the benefit of the Etrex? Better battery life/uses AAs for touring? Assume it can still be bar-mounted? Thanks GPS experts.