The success of the Young & Dangerous series of triad movies in HK spawned many copycats of varying quality. War of the Underworld is one of the better ones and is indeed a good film if not exactly original.
The story is a basic (and well worn) tale of triad betrayal and revenge but the cast is very good (Tony Leung, Jordan Chan, Carman Lee among others) and the action solid... and very bloody. You certainly get your machete worth.
Some of the camera work is maybe trying too hard to be "arty" at times and there is a little too much nonsense about triad "honour" and how they are the descendants of the kung fu masters but that won't spoil your enjoyment too much.