ABSOLUTELY buy a size up if you have a 38-40" waist. I'm ALWAYS an XL in Hanes Fruit-o-the Loom, etc. Not these. These are XXL and they ABSOLUTELY shrink, so take that into consideration, Be aware how many times buying a size up is mentioned in all the other reviews. The material is very nice and is VERY soft. The fit takes a little getting used to if you normally wear "shorts" style boxers, but after a few wearings you won't even notice them. In hot weather they actually DO stay put, unlike regular boxers that stick and move all over the place and drive you insane. If you don't have a butt, like I don't, you're probably used to pulling your pants up frequently especially when doing physical labor, belt or no belt. You have to be aware that it's just your pants falling down and NOT these boxers. At first, many times I grabbed the waistband of my pants AND my boxers and it seemed like these were no different than "regular" boxers. NOT the case. You gotta remember that and be aware of what lower body garment is actually moving. Pay attention and you'll see it's your pants that are falling down/moving, not these boxer/briefs.
As far as the "moisture wicking" properties, they don't feel ANY different than 100% cotton boxers to me to me. No cooler, no drier. No more moisture wicking than regular boxers. However, they DO stay put, which is great. The fact they're not tagless I found irrelevant. I don't notice the tag. In fact, I like the tag, as it's just a little bit easier to orient them when you're late for work and in "panic" get ready mode.
If it wasn't for the significant sizing discrepancy mentioned in so many reviews (which is exacerbated by the subsequent shrinking after the first few washes), and the fact I didn't find ANY cooling/moisture wicking, etc properties, I'd rate these 5 stars easily. They STAY PUT and that's all I wanted. Maybe if I wasn't wearing pants I'd notice the moisture wicking, heat dispersing properties, but pants are required at most places I go.
With that said, they DO STAY PUT providing you aren't inadvertently moving them around if you frequently have to pull your pants up. And the fact they stay put in hot weather, when you're sweating, makes them my hands down go-to warm weather boxers. During cooler weather I'll likely go back to my old Hanes 100% cotton boxers.
I'd absolutely buy them again. I'm already on my 2nd 6 pack. these should be stocked by Amazon so as to be available as a Prime item.