The long stock silencer, a.k.a. "the telephone pole" is not good. Very restrictive, and weighs a ton.
The later model stock header pipe with the "hot tube" reducer in the tail end of it, also is not good. However, it can be recovered by "coring" out the hot tube with the proper size hole saw, to eliminate it, and then it's like most other header pipes.
The India made exhausts have the brackets welded on after the chroming, so they paint over the welds with silver paint. Not good. They don't last very long either.
The "UK made" pipes seem to be made well, and work fine. The look depends on what you like. I like the Gold Star system very well, with the lesser "swept back" pipe that still allows normal footpegs, if you aren't going for rear-set controls.
The "shorty silencer" is popular.
The ones which are empty inside, and use the removable baffle tube in the end give least restrictions, but some people might find it on the loud side. I think it's fine.