I personally don't like Treks, but the Trek is actually my choice between these 3.
The Kona and Spec is nice, but it has hydraulic brakes, which are really nice, but if you ever need to bleed them, you either need to buy special tools to do the job, or pay an arm and a leg to get it done. Trust me, I have Giant Seek2 with hydraulic brakes that I wish were mechanical so I can just adjust the brakes myself. Plus the environmental cost of having to use brake fluid, you can't dump it down the drain. Needs to be properly disposed of. If you drip any onto your bike, brake fluid will melt your paint, the mechanic that bled my brakes dripped some on my Easton handlebar, stripped the paint right off. If it touches your brake pads, you'll need new pads too.

But may I suggest to skip discs all together? They are expensive to maintain, new pads run about $20-30 a pair while v-brakes will run you about $10, if you ever need to bleed them, it's around $30 per brake line. Finding accessories is a PITA too. You need to find extra wide racks which tend to be heavier to accommodate that disc brake, same thing for fenders. The attachments aren't made for discs brakes, and the fenders may end up rubbing on the tire or they sit real close to the tire. I prefer riding on 23s, so it doesn't affect me, but I also have 28s that don't even fit. I know 28 is even too thin for most people here. Also my hydraulic discs squeals like a mofo. Very annoying, and the mechanic wasn't able to get rid of that squeal for me.

If I were to do it all over, I'd go with regular brakes, cheaper to maintain and way more selection to choose from. I would find a bike I like, and probably get fitted with koolstop salmons, they will brake just as well as any disc brakes. But if you must, go mechanical.