I have a 2017 Colorado Z71 CCSB Duramax diesel I've put 42K miles on. I have been a lifelong Toyota guy and relatively anti-chevy person (grew up in Michigan avoiding GM during my Engineering career). I bought mine primarily for the diesel engine, and have to say its been reliable, powerful, and relatively maintenance free so far. I've always driven mini-trucks and Land Cruisers, and moving to this Colorado felt very large at first, even with the short box. I've quickly adapted and truly enjoy getting 23mpg around town and 28+mpg on trips. This is often heavily laden, probably over the GVW and driving highways 75-85 mph through mountains cross-country.
I bought mine just prior to the release of the ZR-2, but I already have good trail vehicles and wanted the Colorado for mostly camping, towing, and taking road trips. It has been adequate off-road, but not tank-tough like my older mini-trucks and cruisers. My suspension is pretty soft and will be replaced soon, with more tuning for towing a trailer.
It comes down to how you want to compromise and balance daily needs, hauling, camping, and hard-core wheeling. The ZR-2 is definitely the best off road, but gives up economy and towing to the "lesser" models. As much as I like the Tacoma's, for me the Colorado diesel has been exceptional. I do have to complain about the 5 foot bed being just short enough to not be able to sleep in comfortably, which was something I could do in my former old '89 Toy p'up, even though it was much smaller.