I have a Frontier and I love it. If I have one complaint it's that it's pretty rough on gas. That said, I got such a good deal on it and was able to get it for so much less than the other trucks I was looking at (Colorado, Canyon, Tacoma) that I feel like in the end the gas price isn't as big of a deal.

Anyway, I drove all three trucks you're looking at. I chose the Frontier because I thought it was more comfortable than the Tacoma, and for all the options I wanted it was a way better price. The Canyon and Colorado came down to sheer price. I will say they were both super comfortable, and had much nicer looking interiors. Not to mention they were better on gas. That said, they were almost too nice. This is going to sound stupid, but I do construction work on the weekends and am generally pretty hard on my cars. If I scratched the bed or the fender of a Canyon or Colorado I'd feel awful. If I scratch my Frontier I wouldn't be as upset because it just feels like more of a work truck (I didn't say this is a rational feeling, just part of what I felt when looking at and driving all three).

In general I'd say check all three out, see what you like the most and pick it. You're leasing so you don't really have to worry too much about reliability (presumably they'll all be reliable for 2-3 years). One last thing to note. The Tacomas and Frontiers are going to be changed pretty drastically next year. Thus, not too many people are buying the 2015s. Because of that, you have a lot of room to wiggle. Tacomas always resell incredibly well, so they can be harder to negotiate on. Frontiers on the other hand, you'll have room to play with the numbers. I got mine for about $8K under sticker (negotiations were long and painstaking, but it was worth it in the end). I honestly know nothing about leasing and how much room there is to negotiate, but you'll get a lot of value on a Frontier.