Ergonomics
I previously owned two top-freezer GE's in a row. However, twelve years ago I was diagnosed with a malignant soft tissue tumor in my leg. Surgery, radiation, then a second surgery to remove infected tissue resulting from radiation. After surgery #2 I had to be in an immobilizer for six weeks, which resulted in permanent loss of range of motion (knee is ok but muscles won't stretch enough to allow normal range of motion). I can only bend my right knee to about 75 degrees, which limits stooping. I pretty much have to bend to reach stuff on the floor.
When this happened, my second GE freezer on top model presented several issues for me:
1. Fresh veggie/fruit bins on the very bottom, hard to reach the bins
2. Fridge is located at the kitchen entrance on the right. I had a standard 18 cu ft model that stuck out 8-9" into the doorway, which created an obstacle. On the other hand, the cabinet gap was a generous 38", so there was room for a counter depth fridge (some cabinet layouts are not wide enough to accommodate a counter depth model).
I replaced the GE with a Frigidaire side-by-side counter depth model. Immediately, it opened up 9 inches of floor space in a high traffic area (the entrance to the kitchen). The model I have has two tiers of bins, plus a fresh meat/soft freeze bin above those two tiers. Each bin has an individual humidity control so you can use it for veggies (high humidity) or fruit (lower humidity).
I stocked the unit as follows:
a. Most frequently used items on upper shelves; least frequently used on bottom shelves.
b. Lowest tier of bins used for cold storage of root veggies and even for products like flour and sugar, to minimize the chance of bugs or ants if stored in cabinets.
I have a saltwater aquarium at home, and a lot of the food is frozen, so I am in the freezer 2-3 times a day to pull out some frozen food for them. A lower freezer door would not work for me, too much bending plus I am in the freezer more often than most because of the frozen fish food. A top freezer would result in too much bending to reach the fresh food. A bottom freezer would result in too much bending to reach the fishes' food, since I'm in the freezer more often than the average consumer. The side-by-side layout lets me arrange things so that most frequently used things are at chest or face level, with less-frequently used stuff stowed on bottom tiers.
Another bonus of my side by side is that there is a kitchen peninsula/bar opposite the fridge. I keep a 40 liter trash bin at the end of the peninsula. With full-width doors, I had to move the bin in order to full open the door (as for removing bins, etc). With side-by-side doors, I can open them fully and leave the bin in place.
Counter depth models have some significant disadvantages, the chief one being high cost per cu ft of space. The largest models go about 24.5 cu ft, but mine is more typical at 22.5 cu ft. All side-by-sides are limited as to the depth/width of shelves, precluding very large platters. However, the extra width of counter depth models somewhat compensates for this shortcoming. Since most of these models are 36+ inches wide, costly cabinet modifications are needed in older homes in which a 38" gap was not yet the industry standard.
The extra cost (about $1700 for my Frigidaire; a similarly sized non-counter depth side by side might have run $1200-1300) for me was justified, since I no longer have an obstacle sticking out into my kitchen entry and the trash bin is no longer an obstacle for the doors of the fridge. I have to bend less and can organize my storage in a more rational manner.