I have the 24x48 offset with the insulated firebox. I've had the cooker for about 3 years now and use it at least a couple times a month in weather ranging from 95+ degrees to below freezing, i.e. mid 20s. I can share some observations from my experience:
The cooking chamber seems to recover faster after opening the doors, this compared to previous offsets I've owned. Now, I do not specific degrees per minute type details, but to me it seems noticeable.
I add a wood every 30-45 minutes to maintain an approximate 275 degree temp in the cooking chamber. Usually one piece of wood every time I add.
My "splits" consist of a regular size split cut in half lengthwise and then each half split vertically, in essence giving me 4 pieces from one "normal" size split.
The outside of the firebox does get hot, but much less than a standard 1/4" would. The paint on the outside of the firebox looks pretty much like new after 3 years.
Living in Texas our winters are pretty mild compared to other areas of the country so to me the biggest benefit is the temp recovery from opening doors. My temp swings just seem to be less drastic.
Hope that helps.
The grilling space seems to be a little deceiving from LSG’s website. How many 14-16lb briskets can you get on that thing?