You may already know this, and are just asking about mechanical specs, but just in case, I'll belabor the obvious.

The big difference is appearance. One is integrated, the other just "built-in." Specifically, the integrated models are designed to be completely hidden behind custom panels. When that is done, the entire fridge/freezer is camouflaged by the panels with no evidence that it is there. With clever design of the overlying panels, you can make it impossible to see that there is a fridge there. Similar for example to the Thermador Freedom columns.

The BI models are designed also to be built in (duh) flush with the adjacent cabinets. The big difference is that like the older SZ's, there is still a large louvered panel at the top. You can cover the doors with custom panels, but no matter what, the louvers must remain visible (for ventilation). Thus it pretty much shouts "SubZero behind this panel." For some, it is a deal breaker (us, for example). Others like the look, esp if they are already contemplating a through the door ice dispenser, which kills the "where is the fridge" look anyway.

I really preferred the layout of the BI over the integrated--it seemed better for short people. :)

The biggest difference is that the integrated looks like cabinetry. The BI looks like a fridge wearing a panel. They CAN look better than the old ones and better than the other brands of paneled fridge, but they aren't going to disappear into the cabinetry like an integrated fridge.

(The other integrated lines, are Bosch/Thermador/Miele/Gaggenau, all sort of clones with different trim levels, and Liebherr.)

I knew the obvious in tat the integrated is more hidden. The built-ins now can also be inset for a more flush appearance though if you wanted.

I love the look of integrated but in my kitchen it would be fairly obvious anyway where the fridge is located since I have Pantry, DO & Fridge only on one wall. The other walls are all countertop.

As Fori said the freezer is shorter thus lowering the fridge for easier access for shorter people. I am 6'1" by my wife is 5'4" and then the kids. So I was leaning towards the built-in but didn't know mechanically if there was any other differences that could sway one way or another. Also the built-in seems to have more overall space vs the integrated models from Sub-zero, Miele, Thermador, Liebherr, etc.

"The built-ins now can also be inset for a more flush appearance though if you wanted. "

Yes, but they require more width and a lot more depth to do this. It's not a simple matter in most installs.

Try to see them installed. I went back and forth, forth and back. I was looking at all fridge and all freezer, which makes a difference. I love the drawers, but functionally, there isn't much difference between the freezer drawers on the 36" and the pullout freezer on the built-in, other than the extra framing that makes them taller.

I've seen the grill covers done beautifully so they don't have the "here lies the SubZero" look, btw.

The installation makes a lot of difference. I don't know if you can get the full swing anymore on the built-in, but that was one of the good and bad things about the old built in over/under. The door would swing open until it bumped into something making access very easy.

The integrated ones have a limited swing, which I find feels a little cramped (lots of big plattering in my family), and not great for pulling out the drawers for cleaning.

The full overlay option on the framed fridges are even worse. They only open 90 degrees.

With both of them you have to do a lift, slide and wiggle to get the pieces out.

I loved the old wire fruit drawer on the built-ins, but I think that's a goner.

At one point I was thinking of the previous model over-under with full overlay and the 27" integrated freezer. It seemed like the only way to get what I wanted, though there was that annoying door thing.

I got Miele.

Really, if you're not sure it's worth finding a place where they're installed so you can really see them.

I would love an all freezer and all fridge but I only have 6" of space for both :).

So in looking at 36" fridges and usable space, etc. It seems that the Sub Zero Built-in wins. My parents have a SubZero 48" Built-in S/S. They did not cover the grill at all. There kitchen is more contemporary so it works and looks nice. I also have a full freezer in the garage and larger fridge is more important. I will go back over to the wolf/subzero showroom and take a look. I haven't been there in a couple of years.