^^^ you bet there is a difference and a big ones too. I did a review with some info regarding the difference between the two, see link below:
www.seabreeze.com.au/forums/Kitesurfing/Review/Sector-60-V2/?SearchTerms=Sector+60+V2Recently I borrowed the North 2010 Ltd again and couldn't believe I used to like it. It is so glaringly different in how it rides, from bottom end to the useful angles to the wind you can go, to the manouvering.
Basically the North was good upwind but other angles is so much work that unless your going into battle with some one and racing, your legs will scream at you 'not having fun dude'! Where as, other end of the scale, the Sector is great upwind, loves all angles to the wind and when your not racing, just ease off and enjoy. You can go for hours and hours, and sure, if you want to race you put the hammer down and push those legs you'll fly around at speed and get your leg burn. I believe that due to comfort, the rider will be faster overall on a Sector than some one on a North Race LTD.
Mind you, price can be a powerful factor when on a buget and if you need to get out in light winds then the North will do it, plus it handles little dings way better than the Sector, but money aside, there is no contest!
cheers,
Robbie