I'm also taking into account the torque specs of the engine. In years past, just as one example, the GMs I drove always had a lot of low-end torque (especially when you first hit the throttle), yet past maybe 3,000 RPM their engines always went flat, with hardly any acceleration. Hondas are known to have a wider torque band, with the peaks coming at higher RPMs. And @BDub also makes a good point about the altitude--I hadn't figured on that. A combination of all that and the gearing is why I struggled a little on that one switchback. (And you know, it's that slight panic attack as it's happening, as I didn't have enough gas to drive all the way around the loop for 60-70 miles and come out the other end!)
My tires are also slightly larger than stock (235s vs. 225s), so the slight additional mass robs a tiny bit of power, and larger diameter also acts against the gearing. But it's probably so slight that it's not even worth mentioning.
I've had the '09 up to the top of Pike's Peak (14,115 ft.), but other than having no guardrails for much of the trip, it's an easy drive and I had no issues. I figured if that Karmann Ghia I followed could make it to the top, I'd have no problems either.
I'm sure Acura's SH-AWD is even better but I can't say that Honda's seemingly low-tech AWD system has ever let me down in routine driving. It's simple, and it just works. There's something to be said for simplicity!