If you are a one bike guy, keep your busa! I have the new Gixxer and it's a kick ass bike but I wouldn't trade my busa for it if I wanted an every day bike to ride. Your busa is much more comfy and does everything the gixxer will do just as well except for cornering and wheelies. The ole Busa Girl is just to dang big and heavy to make a good wheelie bike and she is fun in the twisties but not as quick. Now I'm sure I'll catch some flack form a few guys that will say their busa is fast in the corners and it is, but it's no competition for the new gixxer. Not even close! Your busa will wheelie as well but it's so big you can't see around it nor over it when you are up. Stand ups are best but the problem is if you let the front wheel down just slightly, it's so heavy on the front she wants to keep going down and you use up to much throttle bringing it back up. If you are in third or forth gear it's very hard to bring it back up if you let it drop just slightly below the BP.
Just my two cents worth. The new gixxer for a second bike is a wonderful choice. I ride my gixxer more than I do my busa but mostly for fun afternoons etc. Never take it on long trips, I think it would wear me out? Your busa is way better for two up riding.