Personally, I don’t think it matters. We were on the Expedition in 2017, I think at that time, our cruise was called the inner loop..there have been multiple nomenclature changes for the various loops. Our cruise director, Monica (still on board!) told us the major difference was one saw the red footed boobies and the other the lava tubes..
Seriously, choose whatever fits your life at this point. The experience is spectacular and not to be missed! Crew is amazing and this is truly a bucket list trip.