I'd speculate their decision to go with pushrod design was based on 1) cost/complexity of casting/machining, 2) Overall simpler (considering no ohc drive) & more compact motor, especially with the heads hanging out either side of the bike, ala MotoGuzzi. The heads have to be considerably taller with OHC, especially with a relatively small budget which wouldn't allow for repeated prototyping & material minimization. Way easier, esp. in a V-design, to just stick a cam in the valley right over the crank & with a simple chain or gear drive. Works just fine to, as long as you're not trying to spin it way up. Maybe a distant 3) it's 'murican.
The counter-torque is just nature of the beast & a reaction to the inertia of the crank/flywheel spinning-up. I've felt it on a boxer, and though noticable it wasn't a big deal. That's a V4 mounted relatively high vs. the very low-slung BMW design - and did you see the size of the flywheel in the video?! I bet it has a good bit of counter-torque, but that might just add to its character. Wouldn't be a big handling factor so long as you're changing rpm drastically in a curve - also side-ways V design would lessen the gyroscopic resistance to side-to-side transitions too, vs. typical transverse crank mounting.
All technical BS aside - it does look pretty bad-ass, producing their own engine in-house is impressive, and kudos to them for doing *something* to produce a sporting American motorcycle. I hope they do well & we see good things come of their efforts!
