Okay so I've had a sample of this belt for a few weeks now. I've worn the belt quite a lot in this time, and the TL;DR version is I love it and wouldn't hesitate one bit to buy it at the asking price. A more thorough look at the belt follows.
Since most of the questions tend to be around sizing, I'll start with the objective review around sizes. Having had experience with other BBC belts before, I find that the sizes on the collab belts have been the best and consistent with their sizing guide. MEASURE A BELT THAT FITS YOU PERFECTLY. Typically if you wear size 32 trousers, you would want a size 34 belt. This is assuming that the trouser company uses "vanity" sizing--where the size of your trousers is actually ~2" lower than your actual waist size. Makes you feel good dunnit?
Sizing photo. There is a measuring tape in the center, hopefully you can see the markings if you zoom in.
Top to bottom,
~2 year old BBC cobberly belt in size 36,
BBC dress belt, size 36,
BBCxMassdrop collab (brown), size 34,
BBCxMassdrop collab (black), size 32
I got the mid brown + nickel belt, and is what I will be using. The color on these is fantastic--just the right shade of brown where it doesn't look off if worn with smarter smart casual, and right at home at the more casual spectrum of smart-casual as well. The brown is rich and has a nice depth, not completely flat like most dress belts. A scuff or two wouldn't look bad on this belt imo. Heresy, I know. But this is why I love this belt--a nicely textured scuffed belt in a dress belt form factor? Love. I would personally not wear this belt with the more "refined" (for lack of a better word) outfits--you know, the crisp white smooth-textured shirt with formal trousers and dress shoes. Totally at home with a white OCBD + wool textured pants and brogues, preferably of the boot variety, though. Yes. Beautiful. Maybe throw a sport coat on. Or replace your trousers with slim-fitting jeans, keep the brogue boots, and switch the sport coat out for a chunky cardigan (or not).
In the pic here the bottom two are the collab belts (brown and black), the top two are other BBC belts. You can see some scuffs on the brown collab, that's what I love.
By the way, when I initially got the belt, my knee-jerk reaction was "only smart casual--chinos etc--no jeans". However I feel the belt feels oddly at home with jeans. Or at least with the kind of jeans I have, which tend to be on the skinnier side. I don't think it'll go with the slim-straight or straight cuts, but I might be wrong. Also, at the end of the day, I say screw the rules and wear what you like cause it's your style, don't follow fashion rules that random people online (or elsewhere) make up. Hypocrite? Maybe. But here I go on one of my rants again. Back to the belt.
Materials and construction.
The belt is made up of three layers. The top layer is French calfskin. I actually have no idea which tannery British Belt Co. sources their leathers from, but it feels nice. Then there is a middle layer of leather which gives the belt its beveled padding. The bottom layer, which serves as the lining, is nubuck, which is created from the suede side of the Frech calfskin of the top layer.
The materials feel wonderful to the touch. I love how the nubuck feels to the touch. It'll avoid scratching your trousers, but will also take indigo from your raw denim VERY easily, so keep that in mind. Sizing pics above show how easily the nubuck takes indigo. For comparison, I've owned the one on the top of the sizing pic for ~2 years, and the collab I've had for two-three weeks. I personally don't care about how the lining looks but I wouldn't wear this belt with light-colored trousers / chinos after having worn it with raw denim.
Unlike most belts I've tried, this one feels more flexible--as in, I can twist the belt around its length no problem. The leather seems to crease less than other belts I've tried as well. The black seems to crease more than the mid-brown. I am no leather expert, but I would personally attribute this to two things:
1. The top French calfskin layer is pretty thin, in comparison to other belts I've seen (see cross-section pics below).
2. The lining is nubuck, which tends to be much more supple than calfskin (and most belts use calfskin lining).
The cross section pics around the punch holes lead me to believe that the top layer is actually crust leather which BBC takes and dyes themselves, because it appears to be white. Crust leather is usually used where companies / artists do their own patina (eg on belts or shoes). These leathers tend to age nicely, meaning they will probably change color more than normal calfskin with age. I could be wrong, maybe @AdamJ.Plotnick can clarify.
My comparison of the layers on the calfskin top comes from comparing with other BBC belts I have, and another that was provided explicitly for comparison purposes. In my opinion, this is a perfectly okay sacrifice for what you're gaining instead--an extra $100 in your wallet. :)
In all honesty and sincerity though, I really don't think that the thinner calfskin would matter that much. That's because you're not gonna (and shouldn't wanna) put the belt to extreme use. The belt in a gentleman's attire is not to keep his pants up, it's simply there to complement his garment and other accessories. You should be wearing trousers / jeans that fit you perfectly on the waist, and in such a case there will hardly be any stress laid on the belt itself.
The belt is machine-stitched with a pretty high SPI count. It is cleanly done, and looks nice. I can't find any errors on my belt's stitching. The buckle is stitched-in too. My personal opinion is that Chicago screws or snaps would not have felt too out of place on this belt, but would have thrown it on the more casual side of the spectrum. I know, I know, hardware like snaps or screws on a dress belt?! HERESY. I'm feeling especially heretic today. I guess I like things to be quirky and not normative. *shrugs*
I personally just don't see this belt as a dress belt, per se. It doesn't have a higher polished finish, for example. It's a more... I don't know. Everyday belt, if there is such a thing.
Value for money.
I'll keep this section short. As far as belts go, this feels like extremely good value for money. It SEEMS like it'll last a long time, but I can't vouch for that for another five years. Maybe I'll update this review in five years' time. Who knows.
I was told that Massdrop is positioning this belt as a "anytime anywhere everyday belt", and I must admit they've nailed it on that. I could wear it with all but the dressiest or most rugged outfits, and the belt feels like it'll last long (but of course nobody can guarantee that until they're actually tried it out). But my verdict is, buy it. You probably won't be disappointed.
I'll try and add images to speak to some of the points I've made (eg thickness of top leather layer) when I can.