Two basic types of beacon - older analog (cheaper but won't function beyond 2009) and the newer digital ones. Th enewer ones must be registered, you ma=ust have acontact number (or more than one) where someone who knowns your plan can vouch for your beacon being real .. not acidental.
As far as the gps thing goes ... you pay more for the one with the gps - this will localt the beacon more precisly. There were stories of beanons that could take and external gps input.. don't know if that ever came to market.
Me? - I'd take a gps and a sat phone- much more versitile than a beacon - you can talk to them directly and get the hepl you need rather than an exploratory.
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S