We sail Celebrity almost exclusively (and have 2 more already booked including Christmas on Apex in Aqua) and we sailed Alaska for the first time this year. We finally decided on Princess, our first time with them, over Celebrity solely because of Glacier Bay.
It was absolutely the right choice, we had an AMAZING time and the ship and experience was just as lux as any Celebrity cruise we ever took if not more so in some cases/cruises.
We would go back to Alaska with Princess in a heartbeat, it was fantastic, beautiful and exceeded our expectations in every way I can think of. YMMV.