I had one, and then sold it. Bikes come and go in my life, so don't hold it against the bike that I sold it along.
I think in general USA is reticent about internal gear hub bikes. On top of which, the 3i was a "neither here nor there" style -- is it a cruiser, a hybrid, what? -- which did not fit into any particular category in which people usually shop bikes. On top of which, it was kind of pricey.
It was a blast to ride. If you used anything but the middle cog on your DS, you might wish you had bigger and smaller gears. The bigger gear was easiest to accommodate by just coasting where you might be in the DS big ring; the lower gear might not be low enough if you frequently climbed hills on your ride in the small ring on the DS.
For me, where it fell short was quality -- they rear hub and frame were fine; pretty much everything else on the bike is bargain basement, heavy stuff. The mechanical disk brakes were adequate, but nothing like the hydros you had on the DS. The rims are wide and the tires are heavy which results in a lot more rotating mass than you might have been used to on the DS. The cranks and bottom bracket are more a BMX style setup than a usual BB, and on mine, there was a creak I could just not dial out. Also, less standover on the 17.5 only size of the Moto3, compared to the DS, which may or may not be an issue, depending on your inseam measurement. Finally, compared to the DS, the reach to the bars is shorter, easily solved with a different, longer stem.
On the other hand, it was a hoot to ride, and a perfect casual bike. The big balloon tires made it a hoot, the shifting was great, and the disk brakes on basically a cruiser were awesome.
It's a good bike... with some caveats. If I'd kept it, first things to be swapped out would have been the crank/bb, and the brakes. Then the wheels. And tires. Along with the pedals, seatpost, and saddle. But the frameset and rear hub were solid!
Judged on its own merits, it's a decent, fun bike. Compared to a DS 8.4 or even the new 8.2, it probably falls short.