my wife bought me one. i originally owned a 1986 limited edition gsxr 750 (dry clutch). after retiring from racing and selling off all my bikes, my wife bought me a katana 600. i was like WTF? she meant well, but i gave it away to a friend. then a few years ago, she surprised me with a christmas present. This time, she took advice from a buddy of mine.
I have no plans to mod it. But, i have considered buying new plastics/tank and keeping the originals in storage. I like the yellow paint scheme. from the factory, the suspension is set too tight. the OEM tires aren't the greatest, but i learned it's limitations.
I put a TRE on it, but felt no difference so i removed it.
my wife purchased it for $10k (total including helmet) with i think 13% financing. i was like WTF? so i took over the financing and used two 0% introductory credit cards. i paid them both off early.
as for the handling, i tweaked it to fall into corners quicker (dropped the front about .5 inches and raised the rear end to the max for corner clearance). suspension on both ends are at the middle setting (stock suspension fades to make the adjustments worthless). Sag is about 2 inches (the max before bottoming out). i prefer larger sag for street riding (solo). tire pressure is 5 psi over recommended (i ride in the rain).
cruising range is about 160 miles (commuting). it drops to about 90 miles when hitting the corners (there are twisties in FL - clermont has hills, that's why i moved there).