Chains give a better look, there stronger. and if they do break, its a quick fix in replacing it.

 

While I have limited experience with big inch motors and belt drives, I did rent a Carefree 111 C.I. chopper in Phoenix and hammered for 493 miles (Phoenix to the Grand Canyon and back on aone dayrental). It did not break and the motor was pretty strong (I ripped the rear loose on some interlocking brick street).
IMHO if you are not planning on doing burnouts or dumping the clutch from a standstill, the belt will take the power.

 

I'd go with the chain if you are over 100 hp/ 100 ft.tq. and you plan on riding the bike hard...burnouts,drag race from the stop light, ect. If you are just going to tool around you can get by with a belt.

 

I have a 113 and started out with a belt, everytime I really jumped on it, the belt would skip no matter how tight or loose it was. When I went with the chain, problem solved!!!

 

Have owned a 124" bagger now 6 yrs same belt.Also own a 155" bagger 180+ft lb second year no problems.A friend owns a Bourget with 155" and over 35K same belt,same thing,No problem.We both are aggresive riders.

 

I think chains just look cool. Nothin beats em in that respect

 

Actually just finished watching a DVD with a couple of Boss Hoss bikes one with 800 hp small block,the other a 1000 hp big block both running belts,and doing incredible rolling long burnouts.I guess it is up to you.