Well reading my posts good enough is something even i do not manage that well. Anyway, i will walk with my rucksack, and i think i will not have many contacts with a normal energy net, so the long lasting AA-Version would be a important point for me. Btw your 276C has a nice Display also.
You said, the Montana would be the first category, did you mean by little energy consumption or overall ? Because the price is pretty close to the etrex 35t.