A good question. Taste and texture differences can often be measured objectively but the impressions of taste and texture are often subjective. Additionally, there are more variables at play than cook temp alone.
As important to the result as cook temp is, other variables are as important and in many cases more important. These include quantity of rub applied, quantity of sugar in the rub by proportion, type of sugar in the rub, whether or not sand, water or nothing is used in the pan, and whether a Guru or some other type of fan is used. The differences (or lack of differences) between cooking at low temp might be very different for you using this type rub at this amount and water in the pan than for someone using that type rub at this amount and using a Guru. E.g., you are less likely to see much of a difference in rub texture when cooking using water in the pan at 225 and 275. Someone using a Guru at 225 and 275 might feel more of a difference.
When temps exceed 335 and move over 350 then yet more of a difference is likely (unless one has foiled) because at the lower of these temps true sugar caramelization occurs and above the higher temp sugar burns. Foil, as noted, can mitigate this, as can ambient moisture levels both on and around the meat.
In other words, I'd have to know the variables of your cooks (water, sand, nothing, Guru, sugar type, proportion, rub coverage) before I could attempt to discern what the potential difference might be. And those potential difference might well be quite different from someone else's potential differences if their variables were different from yours.
Much is mentioned on barbecue boards about the 'danger zone' of 40-140 but it is not often mentioned in the post-cook context. If you wish to use extended resting as a variable in your results every effort must be made not to touch the meat at any time prior to cooking, during cooking, or immediately after cooking with bare skin to minimize the chance of depositing Staph aureus on the meat. It is a spore-producing toxigenic bacteria that kicks in when surface temps drop below 120. It should be noted that C. perfringens, another heat-resistant bacteria that might be present on the meat irrespective of bare-skin contact, also outgrows when surface temps fall, in its case when temps drop toward 100 and below. Other bacteria not killed during cooking can begin to mulitply as well. The really dangerous temps are 85-115F, where one sees progressive and rapid growth.
The USDA allows food processors, when they cook the deli roast turkeys, roast beef, etc., that we see in stores, to have these items at any temperature for 90 minutes if, at the end of that time, it is greater than 120F. Then cooling can begin, from 120 to 55F in 6 hours, and continued cooling until the food reaches 40F a total of about 14 hours. Then the food can be packaged for shipment. Why the FDA's recommendations do not follow this protocol I have no idea.
Though surface temps of butts well wrapped in foil and towelled and coolered are likely to stay high for some time, falling temps will occur and this should be noted and monitored if you are going to extend your resting time past 4 hours or so. Again, it is surface temps that are the post-cooking concern of most intact meat cuts--not the internals as is commonly thought. I'd suggest monitoring the surface temps and not allowing those temps to fall below 120 or, if 120 is reached, to immediately unwrap the meats and prepare them for rapid cooling in the fridge or freezer or with ice. Though it will take time for the growth of various bacteria to occur should the surface temps drop below 120, this is precisely the area where timing is critical and precisley the area that is least understood by most home cooks--and by many professionals as well. And it is why, here and in numerous other posts, i stress rapid cooling of items not meant to be served immediately and/or for leftovers.