Well, they all have within 5hp, weight within 10lbs, have the same EXACT same front and rear wheel sizes, inline four, four valve/cyl, four stroke, fuel injected, 6sp, similar gearing, dual disc dual caliper radial braking front, same tank capacity within a fraction of a gallon,
Basically more similarities than differences, compared to tourers, cruisers, dual-sport, twin sportbikes, sport-tourers, two-strokes, motard, etc. etc. etc.
There are more differences between the FZR and YZF, or YZF and R6, or the F4I and RR, or last and this generation GSXR, than between the current crops IMO. They make evolution changes within a year of each other, the competition is stiff.
The only MAJOR differences between those bikes are USD or conventional forks and undertail or side exhaust. Maybe one or two of them have LCD rather than sweep tachs, most of them will have digi speedos.