Here is why I like it:
It fits 42mm tires and fenders in all sizes. It has 650B in the small sizes, 700c in the bigger sizes. I got a 59 which is a 700c bike. I like 700c for on and off road. I have a million cross tires in this size and bigger tires for my 29er and smaller for my road. It makes sense for me. I think if you are shorter the 650b might make sense. But for me 700c works fine. I would not have minded 650b, but I like 700c fine and I think it is the geometry that is much more important that tire size.
Geometry: Low trail sport touring bike. You can load up your basket/front rack and forward weight the bike and not effect the handling adversely. I am hoping for a nice mix of uber-commuter/all-day bike/ campeur/porteur out of it. I will swap all the parts off the complete failure Kogswell 700c P/R over including probably the specialized live rack initially and start playing with it from there.
Tubes: Not super light, but in the sweet spot for my weight and power and loading habits (I think). Go to the website and read a bit more. Tubes are 8-5-8 in the 650b sizes 9-6-9 in the bigger sizes. 28.6 tt and dt. I think this should be pretty much perfect for me. The 59 pleases me in its dimensions and angles, should not fit me small, should be just right...
Fork: Sweet crowned fork with cast in low profile rack bosses. Threadless fork. I will go on record again as saying speccing a threaded fork on a new bike is just silly, especially on a tig welded bike, especially on a front loader. Threadless is better in every way.
Brakes: Comes set up for and WITH brazed on pivot paul racer centerpull. I have wanted to try these for a while, but never had the right bike for it. This is that right bike. Should be sweet. I will report back.
Made in the USA. I think this is important for a number of reasons, but the most important is I am pretty confident that the design-manufacure loop between Rob and the Fabricator is small and easy and the bike will come out as planned.
This all said, there are other options out there, just before I ordered my Rambler, I actually came about a hairsbreadth away from buying a Box DOg Pelican in 650B with similar specs, but the threaded fork bummed me out. However, more choices are always better. I already voted with my wallet in May on supporting Rob and Ocean Air, but even if you don't order a bike, think about supporting his kickstarter to get a nice production run of sweet made in the USA low trail paul racered bikes.