I have one on my bike, it don't get in the way but takes some getting used to. You feel it at first, then disappears somewhere during the first lap.
The biggest issue... at some point you
WILL forget about it when you raise your hand to exit the track. It
WILL kill your engine. You
WILL be trying to figger out how to start the bike while rolling so you don't end up stopping on the track or running into the grass.
Good luck!
Tip... use this to connect it to your hand.
EDIT: I would never use one while racing. Many orgs will combine classes and have a two stage start. Many times during a 2 stage start, they want the 2nd wave of riders to have their right hand in the air. This would not be a good time to forget and kill your engine. lol
I also don't use it while coaching, I need to move my hands way too much and to far. It just won't work out well.