Your kitchen is very large and it seems like you wouldn't be looking at the refrigerators straight on most of the time, at least from what the picture shows. If you need that much room then I think they are a good choice for you. The only other consideration is future replacement, not sure if they will have these units to purchase in the future, a standard 36 x 72" space will be much easier to find.

I would suggest the large FD. I have had both arrangements. They both work.

It will be less expensive to acquire and maintain items that are not built-in. In 10 years, it's easier and cheaper to replace the freezer in the pantry, garage or basement. If you have the matching units and run into problems down the road, you will have to replace both.

What a nice layout! I had considered a 48" side by side built in and did not feel the freezer was large enough. I currently have a 36" full size French door unit and I don't find it to be large enough. I actually love the freezer drawer and it holds quite a lot, but my fridge is always tight on space, half consumed by juice and milk and not much space between shelves. It appears your kitchen can accommodate two larger units such as the Frigidaire you show. Electrolux also makes separate 32" units at a more reasonable cost than Sub-Zero, Your kitchen also seems better suited to a built in or counter depth style. When making our decision, we had considered putting the current fridge in the laundry room but we figured if we are going through all this expense and we have the space, why not store all of our food in the kitchen where we cook? My KD shared that the only regret one client had with a similar reno is that she went with a 48" built in vs. two larger units. These new sizes at better price points a very new and like Danielle Waters mentions, these a a non standard size--something to consider for future replacement or your cabinet design. Personally, I don't like the idea of refrigeration in a closed pantry where I store dry goods.

I have the Frigidaire all refrigerator and freezer. I needed a large freezer that could fit a full size sheet tray and this freezer satisfies that requirement. I have had them since 2008 and they are still working good. They are a little on the loud side. I don't think it looks like too much stainless steel in my kitchen. They are actually not as large on the inside as they might look from the outside. I think the newer models are a bit nicer than the ones I got in 2008. I can try to find a photo of them in my kitchen if you're interested.

My friends have had the Kenmore version of these for some time. They are not built-in, but I believe Sears has had a trim kit available to make them look 'built-in'. They've been happy with them. They also have another fridge with top freezer and freezer in the garage. Those hold overflow and oversize items (they entertain a lot).

I'll mention that Samsung has a new fridge that looks like a 4-door side by side but is actually a FD on the top. The freezer, instead of being a single large drawer for everything, is 6 drawers behind two doors. I think this makes the freezer easier to organize and find things.