Is the Garmin eTrex H or Legend compatible with Linux or VISTA OS?

We are newbie geocachers and want to buy an okay used portable GPS – probably via ebay or craig’s list. (Money is very tight.) When I was reading a customer review of the Garmin eTrex Legend, the fellow mentioned it wasn’t compatible with VISTA. Two of our computers have VISTA. The other computer is a linux (eeebuntu). Will I really have a problem buying an older version of portable GPS? Many thanks!!