As twotonevert above pointed out, pipes (like gear, food, women, etc.) is a PERSONAL thing. What is best for one may be not be so for another. Go to your local bike shop or MnG then look/listen to what pulls in (hopefully, one of them is a Busa) so you have a firsthand idea of what YOU like vs what you can afford.
On a budget? If yes, used slip-ons will get you the "most bang for your bucks." If money is no object...Brocks.