We did Quantum to Alaska last summer. Was fantastic.
The first day and last day are the only ones in open ocean. The others are travelling between islands or near the coast in the "inner passage"
There are great views all the time from the Solarium, and a bonus is that if you walk all the way to the front lower level of the Solarium you can open a door(s) to the outside where you have great views from the "wings" on both sides of the ship.
It's absolutely a big trade-off of more cabin space versus that balcony. Alaska is one place where the balcony was worth it for us. We were constantly popping open the door and getting out the binoculars, etc and on a balcony you can see fully in front of you and to both sides. Very convenient. All other cruises I'm perfectly fine with an inside, and only upgrade to a balcony if it's not much of an up-cost.
If you don't mind the lack of convenience, you can still get great views around the ship but a balcony is a little more protected and easy to pop back into your room to get warm.