I saw several reviews suggesting purchasing your existing street shoe size or sizing up. I tried this and they were too big. My suggestion is 1/2 size smaller than street shoe. It's typical to have one foot bigger than the other. The bigger foot toe will most likely push up into the front. As long as it pulls away a bit when you lean forward it's ok.

Also using a good footbed with high arch can help pull the toe back just a hair.

The ankle hold does seem good with these as indicated by some other reviews. I have very narrow ankles and these are as good as others I've tried. These have a nice inner ankle harness.

The lacing on the inner ankle harness is a little weird. They are laced through this small plastic piece. First get all the slack out of the laces around the ankle. However, the hold is good and feels snug without placing strain on the ankle. I've used the Nitro TLS system with ankle harness and

Then, To tighten you grab the ends of the lace that are sticking out loose, and pull them down and at an angle. This will tighten the plastic piece down to the ankle.

The other laces are like regular traditional laces. First tighten up the lowers. Again pull at an angle and the plastic lace lock will tighten against the lowers. I've read about people removing those if you want.

Tighten like traditional laces. This is a good video with tip on how lace boots to help them from coming loose http://www.youtube.com/watch?v=QbuCotDuRLM

I had hard time getting laces tight, both on the inner and outer. My hands would slip on the lace. But that is just me, I was never good at traditional laces.

One other thing, the footbed that comes with the Nike is the best I've ever seen in a stock boot. It isn't just a sock liner like most junk. It has some shape and structure. That being said, I always use superfeet or a custom orthotic.

I'm not sure yet if I'll size down and try them.

I've got last year's model.

My typical shoe size is 8, with my right foot slightly bigger trending towards 8.5. My feet are difficult to fit in that my ankles are very narrow. Hence heel lift has always been an issue. From past reviews and lots of sifting through forums, the Nitro came up several times for being good for narrow ankles so I tried them out.

They are tight, but given the size decrease and potential for pack-out I knew that. They consist of an inner, removable liner, and an inner lacing system that is different than other boots. The inner lacing system is not part of the liner, it is actually part of the boot. And then you have the dual lacing of the outer boot.

The standard sock liner, like most boots is a total joke. They might as well put a piece of cardboard in it. I've been trying superfeet insoles, and they are a step up, but my feet still throb and am considering Shredsole or Sole inserts.

Getting the inner liner into the boot is very very hard. It takes me a long time to do it.

Getting the boot all laced up seems to take me a long time.
First there is a velcro strap around the top of the inner liner. Then the inner lacing that holds the liner down. and finally the dual outer lacing

The inner lacing system is one of those tabs that you slide down. The architecture of the inner lacing being integrated with the boot instead of being tied with the inner liner is great. It really enables locking the liner and hence heel down snug. It's ashame though that the this inner lacing tab system doesn't stay snug. It seems that I have to resnug it down several times over the course of the day. That part is annoying because it does work very well in terms of keeping heel lift down.

The outer lacing system, the TLS is funky. It's got two laces one for the lower part of the boot and one for the upper. This is nice to allow you to customize tightness. Again it takes me a long time to get things set up. You have to first snug up the laces with your fingers and then pull hard. The retention system is a spring loaded cam with teeth on it to grab the laces and keep them from coming loose. This does work excellent in terms of not loosening over time. You have to wrap the excess lace around your boot and then stuff the grabber part into a little sleeve on the side of the boot. This is a little hard to actually get in on my boot and it pops out sometimes.

Getting out is also a little tough, Pull down on the laces and they unhook from the spring loaded cam.

To summarize. If you have narrow ankles these do work well for minimizing heel lift. Circulation in my toes/fingers is very poor (renauds possibly) so I can't really comment on the warmth as my feet would be cold in anything. The inner lacing system integrated into the boot is fantastic, but in this implementation it does not stay snug over time. The other lacing does work well in allowing you to customize upper/lower tightness and it does stay locked down once set. Hard to get into/out of and time consuming, but worth it for the heel control.