Ride the 650i and 750 both and then decide. I can handle my 750 just fine. The 07's are supposed to be upgraded. I'm not sure about the GC being the same though. When I looked at the 650i and 750, the 750 was noticeably bigger. This was before the '07's came out. Either one, stock or with a simple cdi will fly and do anything you want it to do.

 

Hornsby, the one very important thing you first need to consider is whether you want an atv with a solid rear axle (SRA) or independent rear suspension (IRS). This is where the big difference in handling comes from. Kawasaki's Prairie 700 is an SRA. Kawi also makes the Brute Force 650 in both SRA and IRS. The Brute Force 750 is IRS only. The P700 and BF650 (sra) are awesome handling machines. SRA's handling is very sporty feeling. Powersliding is easy and very fun. These machines are great for fast trail riding. IRS machines tend to be more of a plush ride and are great for slower technical trails, although that's not to say that you can't ride fast trails with them. IRS gives you a tad bit more rear end clearance also. It's really a personal preference. I happen to love my BF650. It handles great and is fast. Almost feels like a sport quad. Just blip the throttle and powerslide the rear end. Very fun. If I were to get a new machine it would either be another BF650 (sra) or the P700. If there were no SRA atvs on the market right now I'd probably go with the BF650i (IRS). Anyway, you really need to first decide whether you want SRA or IRS. This will help you narrow down your choices. Good luck.

 

SRA (650 only) - Excellent for REAL fast trail riding, power sliding on gravel/fire roads, solid/firm handling.
IRS (650 or 750) - Good for rocky/rough terrain, plush ride, hill climbing (you can ride fast as well, but the confidence is not the same as you get from SRA).
Kawi doesn't make 700 SRA anymore - one of the best quads that Kawi ever built.