In moderation, yes. But you dont want to just eat pb sandwhiches for a meal. You can eat one after a meal for extra calories, just be sure not to eat a high fat meal, because pb has quite a bit.
I find that they are loaded with cals but too much is from sugar and starch, so no, they are not good part of a clean diet imo, but they will put on weight
It's cals but if I was gonna eat like that I would just get double cheeseburger. Peanut butter is great but on bread... no. I would much rather have it with some protein powder. Hey apple slices in peanut butter is nice... seriously