I bought mine brand new in 2004, Ptx'd it 16 months later and bought it back a year on from that, from the same showroom, cuz I missed it's abilities.
Mine was/is a 1200S version and is probably the most versatile 'real world' bike I have ridden, (Even after my VFR800). In June 2007, I rode it from N.W. Engalnd to Le Harve, France (via ferry of course), and then down to the Pyrenees, and into Spain and onto Alicante. A 3000 mile journey taking, 2 days there and 2 back on foreign soil,riding 600-700 miles per 10-11 hour day, with 2 days rest in Alicante,
The bike didn't miss a beat. It's soooo comfortable and the 'S' fairing does a proper job of keeping you cacooned at silly speeds. Over these distances at high speed the fuel dropped to approx 30 mpg and I was filling up every hour, or sometimes less. Which meant day time, mid week fuel runs through France. The bike handled well on the none motorway stuff, but I've turned my eccentric axle cams upside down and dropped the forks 12mm, and then wound in front preload to max and rear to 4, just to try and speed up the steering and enhance suspension performance, as standard settings give it a Q.E.II kinda feel.
The engine has huge dollops of pull (torque) and on the fast roads allows you to stay in top (5th) and ride it like a 'twist and go', overtaking every thing like some kind of video game. It was happiest at 5500-6000 revs for this sort of game, that being 90 ish, but it would happily drag you passed anything at warp factor 9 from 60 onwards. This will bring on the need for brakes, which are pretty good. The front wears 6 pot callipers and are the same as on Huyabusas, but need regular cleaning to keep all pistons sliding properly.
I've found that the overall build quality is average to OK, but it doesn't get much better for any other muscle bike. I've replaced all my fasteners with stainless to keep it looking half decent, and with most ZRX's, you can buy an' bolt on a lot of blingy toys, and there are plenty of 'I'm a ZRX owner' web sites, some good, some blatantly run by mid 40's guys stuck in the 80's, maybe that's your bag!
The 'Rex' is a great bike around town too, easy to balance 'n' filter with a standard riding position, allowing you to see properly without straining your black visored Arai noggin into un-natural positions only a ballerina could attempt.
Overall it's nothing fancy by today's standard but is very comfy and very reliable and parts are easily sorted and easy to fit. It's 80's technology (carbs too!!) tweaked a bit, using more modern knowledge and components. Not hyper fast, but will probably out perform your 'real world' needs..I would buy another. Mac