Depends on the bike, I got away with it on both my CBR's but it was snug. I had to use Woodcrafts with a 1" riser on the 250 to clear the top of the fairing just below the bar whereas with the 300 I could use the lower hanging Vortex clip ons due to a change in the fairing design between models.
The Woodcrafts were very well made but I dont like the height of the clamp esp as these clip ons will be sitting on top of the yoke and fully visible. Ditto the ebay cheapies, same issue for me.
The Vortex have a lower clamp height and the Gilles tooling ones that
@Rm1sner mentioned look good too but they dont seem to do the clamp in black which would match the Ninja 400. Also they want $48 USD for postage to NZ!
So... At this stage I'm erring towards the Vortex with the 7 degree drop in black.