My experience has been the opposite in regards to glacier bay and hubbard. Hubbard in particular can be *very* variable on whether you can get anywhere near to it. If I remember properly, I think I've had 3 trips that had Hubbard on the itinerary. One of those ended up in fog and ice, and by the time things cleared enough they didn't have time to go anywhere near. One ran into enough ice far enough out that it didn't go all that close (like, we could see it on the horizon, but it wasn't exactly what I'd call a glacier experience). The other made it basically I think to the entrance of Disenchantment bay, but was still pretty disappointing far away in my opinion. On that trip, we did the "small" boat excursion that took us closer, and I'm glad we did, because it was far better than what we'd have gotten from the ship. That said, I've heard of ships that made it about as far in as the small boat goes too, so it just really depends on conditions. I will say, since Hubbard is actually a *growing* glacier, it's exceptionally active along the front, and is probably one of your best chances of seeing calving of any of the glaciers.

Meanwhile, every trip I've done in Glacier Bay we seemed to get pretty decently close (and I'd say closer than anything but the small boat trip in hubbard). And we've made it on every trip. One of those, even the naturalist on the ship was impressed, saying it was the closest she'd seen the ship get.

If you can get to it, Hubbard might be marginally more impressive because of the activity. But the reliability of actually getting to it leaves a lot to be desired, while the glacier bay trips generally seem to have a much better track record of actually making it (although I know even those sometimes run into problems).