I haven't been in this forum for awhile, but havong owned a CBRf2 and an R6 here are some thoughts to consider along the lines of what everyone else has posted...
Firstly, congratulations on making the smart choice of the GS for your first few years of riding. Undoubtably you're progressing well from having started off on a good standard bike. Three years seems like a good time to move up.
The f2/f3/f4's ergonomics are are similar and thus very comfortable for sport & touring in comparison to the R6, which really is a pure sport bike best suited for the racetrack. The R6 puts you in a position that tends to put lots of weight on the wrists and thus longer trips are less comfortable. The engine of the Honda's is more user friendly too. A better spread of power, down low, not that the R6 is hurting down low, but the Honda's are very smooth, very linear, etc. The R6 loves to rev... rev rev rev... and despite my love for Yams and the R6, if I were riding it on the street I'd opt for the CBR and tend to agree that the YZF600R is a better choice than the R6 for street duty and sport touring. (The R6 rules at the track and for agressive sport riding). Point #1 is the YZF600R has a WAYYYYYY comfier seat than the R6... the R6 seat is a plank and sucks for long distance compared with the YZF600 or the f4i). The R6 also has pretty limited lock-to-lock steering for tight manouevers when doing pedestrian street things in the parking lots etc... So back to the CBR f-series: these bikes are also known for being easy to ride fast. Check the height of the bikes out, i think the f4i is shorter, as is the SV. The R6 has a pretty high tail height, but i don't notice these things too much as i am of reasonable height.
I think you'll find the SV has lots of potential and is a fast enough bike when ridden well. Nice useable power for around town too. They sound great with a pipe too. The GS500 is a dog for engine power compared to any of your choices. The SV will do you well in every area.
Another bike coming down the pipeline which may be of interest to you is the new Kawasaki ER-6:
http://www.totalmotorcycle.com/photos/2 ... -ER-6n.htm
The best way to keep up with a Hayabusa is by spending money on taking riding courses, and learning to blitz your hubby in the twisties
, as a very good rider on a SV will have no problem staying AHEAD of the average rider on a Hayabusa. And some of us men (snicker) are slow to learn, and thus opt for big horsepower rather than decent handling... so use keepin using your head and learn to get ahead
You can save the money not used in purchasing an inline-four 600, and go with the 650 V-twin, and spend the rest of your hard earned cash on your riding skills, taking advanced/performance riding courses over the next few years and every year afterward. It pays dividends in spades because the real fun is in the twisties, and any bike ridden well in the turns is fun. Over the years as your riding skills continue improving you will be much better prepared to appreciate each step up in new bikes...
BTW: if you choose the SV, one common modification for serious sport riding is different springs and valving in the front fork. Other than that it seems like a good bike from what friends have said over the years.
Sit on 'em... try some test rides, etc... get ready for new fun...
"Zounds! Zorched by Zarches, Spaceman Spiff's crippled craft crashes on planet Plootarg!"
For Sale: Ninja 600 with parts bike, needs minor work, $30, no title... (GEE THAT DOESNT RING ANY WARNING BELLS DOES IT?)