I use a 14t front sprocket on my 1100 Evo, my observations are.
1/ Better initial pickup and acceleration with smoother low speed town work (even better with Rexxerr flash).
2/ Very little loss of top end, not that you are supposed to be going that fast
3/ No real cons, some say it makes the chain rub on the swing arm, i fast road ride also the odd track day and never had an issue.
4/ It is far cheaper to put a 14t front sprocket rather than a 3t larger rear sprocket and new chain to suite on.