I didn't go on the Tracy Arm glacier excursion, but did talk with some folks who did. They all thought it was great. However, the 2 favorite excursions by consensus towards the end of my Mariner Alaska cruise were the Neets Bay Bear Watching (in Sitka or Skagway I forget which one) and the Whale/Otter watching with Captain Larry. I did the two latter excursions and thought they were absolutely amazing. I've got some great pictures (silver halide - I don't believe in digital cameras) of otters. We got SO close that I can see their whiskers and littler fingers. Saw lots of bald eagles, 3 breaching whales, and some seals as well.