A side-by-side model was already in a house I lived in and couldn't wait to get rid of it. As someone already pointed out, the freezer was too narrow for a pizza. Plus, the refrigerator side was narrow, too. Whenever I planned something like a holiday meal that required large roasting dishes or casseroles, it was a major undertaking moving everything else around in the fridge just to get those containers to fit. Never again will I have a side-by-side.
Currently, and for many years, I've had the freezer on top model. Like it a lot because there's next to no bending over. Yes, the occasional frozen whole chicken does try to escape, but they're usually exiled to the stand alone upright freezer in the other room.
When Glenn and I got married, he was in the market for a new refrigerator, so we looked at a lot of different types/brands. We were leaning toward the freezer on the bottom until I talked with a childhood friend who's been in the appliance business for over 40 years.
He said the freezer on the bottom models are convenient but, until the industry gets some of the bugs out, we'd be better off with a freezer on top. He related that, for some reason, the motors/compressors/etc. fail quite often with the freezer on bottom appliances and that they are quite expensive to repair. More so than the traditional freezer on top ones. The refrigerator we were considering was quite a bit more expensive than a comparable top-freezer model, so we went with what we knew and have been quite happy.
Just my two-cents' worth.