Hmmm - this (general) topic seems to come up often. As many responses already implicitly suggest, you might consider the following: the real (as opposed to subjective) difference in average/sustainable speed at a high pace is between road geometry/drop bar (road race, cross, light touring) and off-road geometry/flat bar bikes: the former place you in a more aerodynamic position which utilizes different muscle groups in pedalling -- wheel size has nothing to do with it (gearing can be altered easily to account for this). I would suggest that the Bad Boy feels fast (and is prob. faster) than your old mtb simply because it's lighter, has better rolling tires, and road-oriented gearing. If you switched (as you could) to high quality 1.5" slicks on 26" wheels on the BB, very little if any real difference in speed, imho. Put another way, as others have suggested, think through what you like/how you will use the bike. If you like sustainable high speeds, stay mostly on pavement, why not a good road or cross bike with suitable tires? If (as you say) you really like the mtb feel/position, and do spend a good amount of time off-road on non-technical terrain, then why not just get a really good, light h/t (e.g. instead of the Bad Boy buy an F600 or [now] Caffeine F3) for less money and put on appropriate tires/perhaps play with the gearing if necessary. You'll fly past riders on knobbies just as well as with the BB, and even with the BB you still won't be able to play with the roadies!