never ridden a 650, i bought my sv1000 as my first big bike so im a little 'blinkered' by it. fuel wise i think its decent on a run out, but then it all depends how throttle happy you are, the most ive had out of a full tank is 175mile until the light stayed on (1L left)
Handling wise i have never ridden in to anywhere near what its capable
Also i dont think its mega mega heavy for a 1000c, i think its approx 186kg according to specs ive seen
Rob - if you are fancying a try on a 1000 then you could have a little go on mine