I'm pretty impressed with that Stihl and the 20" oak. I don't know much about chainsaws, but even I thought it was a slow cut. But it did get to other side of the log, and that's the key point.
I'm not running out to buy a chainsaw right now, but I would give something like that a try.
That's an option, but with urban trees you can't always get your vehicle that close. It's worth considering, though.