1HBH suits for fast, low bounce courts
Better for attacking style, net-rush, volley(and half-volley), more reach and flexibility. Better striking zone, slice is more affective, more topspin, less prone for error.
2HBH suits for slow, high bounce courts
Best for baseline basher who thrives on long rally, playing safe. Defense/pusher specialist. More compact for grinder(I.e. Djokovic) relying on wearing out his opponent physically. ROS on shoulder high, and less prone for shank
With that being said, mastering 1HBH is more difficult because it require a higher degree of innate talent, skills and athleticism. Aesthetically, 1HBH looks more sophisticated and manly, and pleasing to the eye.