Be safe and happy with an unobstructed balcony. There are times you are just cruising the passages and it's nice to view them as you travel. As for circling to view the glacier, the ship did a 360 for us, but I went to the upper deck to view all the angles. We were there in a September and it was very chilly, wore layered clothing up on deck. If you were in a super obstructed balcony, you'd miss part of the view, and if you take pictures, you don't want the obstruction in those pics.