Came across a used Kona Jake. I think it's a cyclocross. Just wondering if it would make a good commuter. My route consists of stamped gravel and pavements. I don't know how much of a improvement in speed over my current hard tail mtb with road tires. I may very well be the bottleneck frankly. But any help is always welcome yes? Or at least that's my excuse!

If it fits you, it'd be a good commuter. As for the pickup in speed versus your MTB, that depends on your route, gearing, etc.

Yes. If it fits.

Its a great commuter, I ride mine every day.

route is about 16km long.

I ride my Kona Jake 22 miles round trip daily. It's an awesome commuter. Reasonably light, plenty of room for fenders mount points for rear rack.

This one's an 06. Don't think it has the nice Deore and Tiagra parts. it's Sora. Are they bad?

They aren't as good as Tiagra, but they aren't bad. The one complaint I would have is that the release lever to down shift is placed awkwardly relative to the position your hands are in when you're riding in the drops. A lot of people don't seem to mind this.