I'm a non foiler on ribs and I love it. I tried the 3-2-1 a few years ago and results were good. Just got lazy when it was time to foil and said screw it. The texture of the rib is much better I think.
As for the butts it's not that I prefer to foil but it seems like all my cooks start late morning and by late afternoon/early evening I want to clean up everything before dark so I will then foil the butt and transfer to the oven to finish it off. But it is on my to do list to take a butt start to finish w/ no foil.
I don't foil the ribs until they are ready to come off and "rest". They either go into a warming box on the smoker, or into an ice chest. If it's a big feed, we will pan and cover rather than wrap individual racks. Those are the ones that generally go into the warming box of the smoker.
I have only done two brisket's, one butt & 4 racks of baby backs. So far, I have foiled everything & it was the best meat I have ever put heat to. I am scared to try it any other way. This weekend will be two spares & another butt.
Plus, it gives me a chance to play with the shiny stuff.
I've been foiling them in the past, but tonight I did a 6 hour smoke with no foil, while misting them with apple juice, cider vinegar, and olive oil mixed together every hour or so. I think they came out pretty good, but they won't get eaten until tomorrow afternoon. :-(