I have ridden the GS 1250 for about 3 years and few cruisers but never been on any sports bike. My main concern is to get a bike for the weekend fun and maybe on-track racing. Ninja 400 with parallel twin and DOHC looks quite a decent bike.
Have few shops around where they work on the bikes and the people there suggested choosing between a ninja or a monster? I visited a few places today and I really liked the Ninja 400 looks and Specs plus this way I will have a little peace of mind that I am not buying someone else problems.

Lol.
BTW, what would you recommend for the luggage? Is it really practical to put a Tank Bag on a sports bike? would it not be hard to drive the bike as the handlebars are quite low and you have to lean forward to grip them?