"best exhaust" is always relative, depends on your personal preferences, availability, durability, maintenance (change fibers) etc.
There's also more brands in production: FMF, Yoshimura, Rossier, HMF, Ron woods
I'm using FMF mega-bomb (titanium) header plus factory slip-on FMF. Runs very good, more bottom end comparing the power-bomb header (steel). Even that I don't like the attach system of the header using "springs". They tend to become loose making the header moves.
Titanium is expensive, but lighter and don't become rust with dust and mud.
Also I use a big width metal clamp to attach the header to the slip on to avoid movement and leaking air, wich annoying me. When it's new there's no leaks, attach perfectly, but mounting and dismounting always there's a few gap