You're right -- sectional garage doors are more expensive than the fixed overhead type, but they do have a few advantages that, in some cases, really justify the expense.

We have found that many folks believe the sectional door is prettier than the solid kind. Since appearance is strictly subject to personal preference, we won't study that issue here. But, there are a few functional differences that are quite important:

1. More head room -- Unlike the fixed overhead door, which opens into the opening, a sectional door opens up and behind the framed opening. This provides 6 to 8 inches more opening height. And, if you have always wanted to get your van or 4-wheel drive into the garage now you know how.
2. Easier parking -- In urban areas where garage doors are closest to the sidewalk or alley, and in situations where the driveway is barely long enough to park your car, the straight-up opening action of the sectional door (as opposed to the swing-out action of the fixed-type door) can eliminate the problem of parking in the driveway and using the garage door at the same time.
3. Better weather protection and a neater trim configuration -- Since the sectional door moves straight up (or down) as it is opened (or closed), it is much easier to seal at all edges. A close inspection of the two different types of doors installed reveals that the sectional door seals better at all four edges than the fixed type. That can be nice on a cold, windy winter day, and it gives a cleaner look.

Use caution when selecting a sectional door. Sagging at the middle can be a problem. Installers will use a center track to help prevent the problem, but the better metal doors incorporate stiffeners into the back of the door that will prevent the problem altogether.