I fitted them to my previous bike (TDM900) as the lights were terrible, but the tigers lights are so good I don't think it needs them, better to add auxiliary lights to increase visibility IMO.
Pros are a very white piercing light.
Cons are they need a warm up time before they are at full brightness and you'll probably have oncoming cars flashing you a lot unless you dip them a lot. Also you need special ones if you want a main beam - on the TDM I only changed one light to HID and the other remained as a normal high beam.
You can get cree LED auxiliary lights now that are as piercing as HIDs and less effort, so id just go down that route like I say.