I have a very positive reaction to both of these shoes. I have avoided Nike shoes for many years preferring Brooks or Asics. In fact, prior to getting these shoes I can't remember the last Nike shoe I ran in. The Flyknit is very well made light weight (9.2 oz for a 11.5 for the trainer and just a tad under 7 oz for a 11.5 racer). Size wise I took a 11.5 in both shoes and this is my standard size that I take with Brooks shoes. I could have taken a 12 for the racer but using drymax hyper thin socks or no socks the fit is fine. Run feel is pretty solid no mushy feel and you do feel the road. The shoes are pretty narrow which for me is fine as I have a very narrow foot but if one has a wide foot forget it.
Pros--this shoe is lightweight (the racer being really light and you feel like you are flying), very breathable due to the flyknit construction (though I would not run in the rain with this shoe unless you want a wet foot), the racer has a glove like fit which I really like, and lastly very striking looking.
Cons--Very narrow (wide feet should not apply) and No in the rain running.
Wish list-- a wider toebox and lower heel drop.