My usual suggestion is a tunnel over a geo as they're lighter for the same space and still remarkably tough, but the place I personally use a geo is for paddling trips, because you can end up pitched on wee skerries that only have a passing acquaintance with soil and that can make pitching a bit of a game. From my paddling experience thus far, it is a not uncommon experience on the Scandanavian coastline where plain rock is remarakbly common.
The porch on the g2xt will need pulling out, but you can tie that to a boat or something and the main tent will stand up okay on its own.
For hiking use I'd prefer the tunnel: lighter to carry, quite tough enough, a bit less fiddly to pitch, but for the paddling I'd take the geodesic: of course, haing both would cost quite a lot! .
Another more expensive option would be something like a Hilleberg Allak dome, which is ideal for camping on small plates of rock in fjords or the Baltic as it doesn't even need the porches pulling out (all done with internal tension). You don't have an extended giant porch, but on the other hand you do get one good sized porch each. It's also light enough to carry for the hiking trips, but it does cost quite a bit more.
Pete.
