Hi, Timothy,
As one who vapes at both, I can give you my opinion based on experience. 801 attys, at least, work much longer at 3.7 V than they do at 5 V. Also, at 3.7, they sometimes last long enough to get all gunked up and develop high resistance. At 5 V, they die before they ever get that bad. (But, hehe - that's not nearly as hard on them as
vaping at 6 V is. I had terrible luck with attys when I tried that for a day.)
I think the
juice is a large part of how clean the atomizer stays, but the part that gunks up is not the gray, sintered arch you see when you look down the barrel, it's the heating coil that's under it. Getting black chunks in the top of the cart filler is a sign that coil gunking is occurring.