Having both, a 99 Busa and a 05 R1...they are very similar but also very different. The 1st thing you will notice is the weight. The R1 will come much less on the scales.
The power to weigh ration is close and depending on mods, might even be better on the R1. However the power delivery is completely different. The Busa as you know pulls well at any rpm, the R1 with much less tq, you have to rev it to the moon. My R1 at 10k rpm does its best to separate my arms from my shoulders.
On the road you will notice a machine that handles much better than the Busa. Side to side transitions are made with much less effort. The Busa can hold its own, but when the pace quickens and the road gets tighter, it will be much easier to keep up a quicker pace on the R1.
Both bike have so much to bring to the table. The R1 is my dedicated track machine and the Busa is mainly used for quick road blasts.