Cycle Torque is riding the latest Kawasaki Ninja 1000 [Z1000SX] on public roads rather than a racetrack, because that's where most riders will be riding the bike.
The ZX-10R is a Suoersport machine, the Ninja 1000 is a sports-tourer. Less aggressive riding position, optional luggage, more weather protection. Lots of other differences. Watch the Cycle Torque videos on on both bikes and check out cycletorque.com.au for the road tests.
I've demo-ridden the GSX-S1000 but not the Ninja1000, although I've sat one the Ninja on several occasions. The K5- based 999cc GSX-S engine is a riot. Makes bags of torque and is less vibey than the Ninja at 5800-8000 rpm range. However the throttle mapping is a little on/off due to emissions regs in the Suzuki. Articles have said the Ninja is super smooth in that way. Suspension and chassis on the GSX is super stable and confidence inspiring. The 190 rear tire not affecting steering in any bad way. Ninja will have a lot better fairing for wind control. Even the F model Suzuki has little better wind blocking than the naked version. Suzuki is less expensive somewhat. I think the Kawasaki is the technology and package winner by a good margin. Suzuki is the horsepower and weight winner, with really decent basic TC and ABS, but without IMU controls of the Kawasaki. Gearing on the Suzuki is the biggest issue. Very tall 1st gear (lots of clutch slipping needed to get a good launch) and 2-6th are all on top of each other. 6th gear has the engine spinning 4,200 @ 60mph. That's about 400 rpm too much for a big powerful engine like this, but it still achieves about 42 mpg from what I've read. For gearing data, check out www.gearingcommander.com For ergonomics, load the bikes and your body size on the tabs, www.cycle-ergo.com Ninja can be tuned to achieve about 140 rwhp with full attention. Weight losses are pretty healthy with exhaust. Suzuki can be tuned to achieve about 153 rwhp with full attention. Weight losses are less dramatic with mods.