A balcony does not make or break a cruise for me. If the price is right and I can spend the extra money I usually go for one. If not, I'm still very happy with the cruise.
I'm always up near the pool or the hot tubs anyway so I'm always in the sunshine.
A balcony is nice to dine on. Very peaceful and romantic. I like it for the solitude. There are times when I want to be outside but not around noisy people. So for relaxation it is great.
So the answer is personal choice.
What I look for most of all when choosing a ship is the right cruise line and ship. Each has their own personality. It depends on what you are looking for.
What activities do you plan to do while onboard?