I have had both, and they have been great motorcycles. I would throw Honda and Yamaha in the mix too. Depending on what you like and what your priorities are, Buell makes a great sport bike too.
I don't think you can go wrong with any of the "Big Four" though.
New rider? Buying new? I think the 250 Ninja is a great deal, but the SV650SF may be the best moderately powerful sport-bike out there.
I have been riding for 20 years and currently own two sport bikes, and that SV650 really interests me. It would be perfect for an "extra" motorcycle for friends to ride when they are in town, and I could take it when the GSX-R1000 was the wrong tool for the job.