so you are comparing an oversized aluminum bike to a normal diameter steel one? as far as stiffness go I would bet that the 735 is more stiff then the BK, but then again you need the exact opposite for street use, a forgivable ride without feelling mushy.
What I can say is that my Leader 722TS (not the heritage crappy looking one btw) is a great commuter bike, good geometry, good toe clearance, it handles me dropping of curbs everyday for a whole year without any problem and is much cheaper then a BK. The downside is that it's not a light frameset but I do have the steel fork, don't know how much weight the carbon fork would shave.