I took a look at one of these and my chief gripe is how cheaply made it is. If someone like Airstream were to put one of these together it would be a totally different story I think.
Its a great concept, but it is full of things I personally would never use and lacks several things that are important to many builders on this forum. I don't personally have, want or need any hook-ups, a black tank, or permanent in-van cooking. The bed is novel for hauling things, but most people looking for a full on RV in a van are not using it to make trips to home depot. It lacks safe seating for more than 2 people, is cramped inside (as in, I would not want to hang out in it in poor weather) and definitely wont sleep more than 2 people. Additionally, it has a lot of equipment slung under the van and has no provisions for secured external storage.
I see a lot of builds on here being designed with a double platform bed, or a pop top plus lower bed, retaining a factory bench seat to bring kids and family along and overall having more modularity than the Revel has.
While 100K is a pretty reasonable price for everything included, its only a bargain if you want all those things and don't what what it doesn't have. Clearly there are people for whom this is the case, and if you are one of them, then definitely buy it over building your own. That's a no brainer. Your time invested will push you north of the $100K pricetag of a van with a warranty that covers all the camper systems on top of the van. For me it would be a no-go as I need to safely seat 4, sleep 4, have room to hang out in the van on occasion, have better ground clearance and a lack of low slung equipment underneath, and have accessible external storage (ie no on the roof).
I am into my van for around $87K, and to me $13K is a LOT of money, however you slice it. Yes I have probably 100 hours worth of work into it, but it does everything I need, nothing I don't and it doesn't have stupid decals on it. Not to mention I know how everything is put together and where everything is if something happens to break on a trip.
Kudos to winne for seeing the market opportunity with the demise of the E350 and the rise of #vanlife in a generation who values exploring the great outdoors. Hopefully enough of those young adventure seekers can find the scratch to pick these vans up and warrant an expansion of the segment by other players with different approaches. While a larger industry is not good for those of us trying to find solitude in the great outdoors, it is certainly a boon for the aftermarket on these vans. The more entrants there are the more and better equipment will be developed for the sprinter. In my mind those are things like advanced aftermarket suspensions (intermediate/long travel), locking differentials, plug-n-play electronic upgrades, customized RV related equipment, adapters and bracketry etc etc.
Im looking forward to seeing where the Revel goes and who else gets on board.
It really depends on what the cabinetry weighs. 
