The Ranger is an awesome truck; I'm quite smitten with them, anyhow. I was giving them considerable attention when I purchased my F350; the missus talked me away from the Ranger due to my physical size. I'm sure she was right, and that after a while my knees would not appreciate the smaller interior, but I was really impressed with the truck.
I can't say anything about the current Colorado/Canyon, as I know nothing about them other than they were just redesigned. I think they look nice, and I'm pretty sure the one next to me at a light the other day was a small turbo diesel, it sounded great.
Both trucks are really popular around here, so I'd imagine they're both rather nice.