I have a 08' Bad Boy Ultra that I have been using as a commuter so I will give you some of my thoughts on the bike. Like you, I really was drawn to the "look" of the bike and because of that, disregarded some of the other models. I do live in Japan though where 95% of people ride around on what you would normally get at someplace like Walmart, so I didn't have the selection that you do in the US.
What I like:
-The black stealth look of the bike. Its just cool, and the reflective decals are very unique.
-The Caffine frame has been a solid performing hardtail for Cannondale for a while now.
-I like the 48/36/26 gearing, its a nice compromise between normal mountain bike
gearing and a road bike.
What I dislike:
-The Avid BB5's are really just worthless. I hated them, they are gone now.
-As far as 700c tires go, you are extremely limited on what you can fit on the bike.
The Headshok has a air valve that protrudes out of the bottom of the fork and limits
the tire clearance. I currently use Schwalbe Marathons in 700x32 and they barely fit.
When I say barely, I mean they have like 1mm clearance. Forget running anything
bigger than 700x32 and expect a lot in that size to not fit at all.
-You are paying a premium because of the Cannondale name, but you probably know
that. For the price, there are bikes with better components.
-The saddle and Welgo peddles both are awful, they went immediately.
-I really don't like the SRAM X7 derailleur. I have had a lot of problems with it. I have had less problems with Shimano XT.
Things I have changed and recommendations:
-Upgraded to 2008 Avid BB7s with Avid Speed Dial 7s levers. Braking power has
greatly increased and the SD Levers are cheep and the BB7's adjust well.
-Upgraded to a Thompson Setback seatpost and a Brooks B17. Big improvement.
-I use a Topeak MTX Rack made for disk brakes, it fits the frame perfectly and has worked out well.
-If you want fenders I would recommend Planet Bike's Speedex Fenders for 700c. They mount to the chainstay and the fork. Disk Brakes make traditional fenders all but impossible to work with.
While I do really like the bike, and I love its looks, it is by no means perfect. I have personally found that I really don't like 700c tires. At least not in size 32 or smaller. I am just too used to mountain bikes, and these things just don't appreciate you going off of curbs or jumping them. I think I would have been happier with a 29er where I could put any tire size on I please.
I have found that commuting daily is much harder on the bike then I ever was doing trails on the weekend. I am constantly having to tune the bike up, have had to true the wheels a few times for taking those curbs as well.
I have decided to put 26" wheels /w some slick tires on the bike and I am going to swap out drivetrain for a Rohloff. I am hoping it will be the trouble free low maintenance drivetrain I have read about. An expensive move, but this is basically my car. Got sick of the price of gas, which is even more expensive here so I sold the car. But, honestly you don't need a car in Japan.
If I had to do it over again, I would just buy a frame and build it into what I want.
I would love it if you could buy the Bad Boy Frame though, for its looks at least.
Hope this helps you decide. Let me know if you have any questions.