First, are you considering last year's (2009-10) Nitranes, or this year's (2010-11)? The photo is definitely of this year's model, but normally just saying "2010" now means last year's. The reason I ask is that last year's Nitranes had an issue with the toe straps tearing. Ride developed a stronger strap and sent out replacements. The 2010-11's should be fine, and the 2009-10's with the replacement should be fine, but the 2009-10's without the replacement might cause you inconvenience.
As to your question, there have been multiple threads just in the past week about Contrabands versus other bindings. Check 'em out.
You're not going to get the same "death grip" feeling over all your toes as you would with a normal cap strap. Thats not needed though. I have never felt my toes weren't secure enough. It doesn't directly strap down your pinky toe but the strap connecting the toe piece to the ankle secures the top of your foot where normal bindings don't.
so basically you say if i want to feel fully gripped, go with the 390
now which of 390's should i buy? the regular one, or the boss?,
are the "wediges" of the boss good? is it comfortable?
The contrabands has as much foot support as any 2 strap binder. You only need to use 1 ratchet on each foot which is a huge plus. I dont think the wedgies would offer a lot more pop but they seem to be very comfortable. On top of that it's lighter. I hear the 390's are nice, dont know much about the 390 but if you are split 50/50 I would just go with whichever is cheaper.