I have riden both 14m and 10m Nitro/Switchblades back to back. I like both alot, but none of the differences are significant enough to justify the price difference.
In February, I spent 2 weeks in Saint Lucia. While there, I rode my 14m Nitro3 back to back with my friend's brand new 2014 Switchblade in near perfect conditions. And in January, I rode my 10m Nitro3 back to back with a 2010 Switchblade, while snowkiting on the upper Mississippi. In both cases, I was very impressed with the long, consistant throw of the Switchblade. The Nitro3 has about a 12 inch long sweet spot, whereas the Switchblade has maybe 18 inches. I see this as the only positive for the Switchblade over the Nitro3, as it produces a very smooth ride. However, when ridden properly the Nitro3 can give you just as nice of a ride, with the added benefit of a quicker and more complete depower, when you need it.
The height and hang-time of both kites are awesome and essentially equal. Relaunch is easy. And the built quality of both are the best. The Switchblade has a larger LE diameter, which gives it solid stability, yet slightly slower turning. And there's no question that the Nitro3 points further upwind and will take you there in a hurry!
Other important differences maybe more personal. I don't like the Cabrinha's QR, because I think, reloading it in the water would be very, very difficult. (However, the need to do that should be rare, yet very important.) I also don't like any strap-systems. I much prefer a simple cleat, because it's position is accessible, adjustable, and provides greater range. I also prefer Switch's new single-line-safety bar system, over the larger diameter, spongy Cabinha bar. Both kites have the much needed large diameter, inflate/deflate valve...which is an absolute must for any kite in this day and age!