Since many people are going to spring for a 1 or 2 mg card anyway, the extra memory isn't a factor. So unless you're intending to use this for marine purposes, the question become, why wouldn't you buy the more compact, easier to hold model?
Excellent point and unfortunately I haven't had the opportunity to hold either one of these units. The 76 shows to be a little more than a 1/4" wider (2.7" - 2.4") than the 60, a 1/10" taller (6.2 - 6.1), a 1/10" deeper (1.4 - 1.3), and finally 1/10 oz heavier (7.6oz - 7.5oz). Anyway, with these specs being so close compactness didn't seem to be an issue however the 60 being easier to hold could be a factor. Another decision to ponder.