Bolting down Union Park East on a crotch rocket is thrilling and all, but hardcore choppers are more my speed. The Hexer and the Wayfarer are some amazing bikes, in both driving ability and appearance, but my all-time favorite is the Revenant.
Mine would definitely be the Hexer, although it's an unfair opinion since I haven't driven the other bikes as much. I like the Hexer because the feel is different. I guess a lot of it has to do with the fact that Johnny's Hexer is uniquely one of its kind. I find it unsatisfying to drive other bikes after driving mostly Johnny's Hexer.
Definitely the motherf*cking Hexer, by far the best bike in the game in my opinion. i guess that's mostly because I haven't really used the other bikes as much. but i just can't bring myself to ride another bike, i do sometimes but the feel is different imo, Johnny's Hexer is just unique. Like Allen14n said, it's really hard and unsatisfying to ride the other bikes after using Johnny's Hexer.