Historic Range: $36.00-$88.99
230 g / 8.1 oz
4-13 (half sizes) and 14
First of all, it is worth noting that despite Backcountry Outlet's comments, they are not a female-specific shoe: I'm a six foot, three man with size 12 feet!
I use them as an everyday shoe, as I'm getting into the minimal shoe thing, a la Christopher McDougall (author of Born to Run), but their intended use is as a 'racing flat', on short hardpack/rocky/dry grass trails and road.
The sole is thin, allowing excellent trail feel, which of course can be a bad thing on stony trails! The upper is very minimal and snug fitting; they are very breathable and drain well. The downside of this is that when you accidentally kick a stone, you know about it! I wouldn't mark it down on its limited protection, as it is in keeping with the shoe's super light weight.
I love using them, and not just for short runs: I have done two 20 mile trail races in them. They certainly make me feel fleet-footed. However, I am knocking a star off because they are not very accurately sized. They tend to come up pretty small, I think because they are very narrow: I have narrow feet and still find them only just wide enough. Don't be surprised if you need to go a size up to get a fit.
Still, if you can get the fit right, they will give your feet wings!
Update: October 15, 2011
This is an update of my previous review — Inov8 seem to have sorted their sizing out, so the later generation of F230s should be a more standard fit.
Materials: Synthetic mesh and rubber
Use: Road and trail racing, fast training
Weight: 0.23kg/size 9 shoe
Price Paid: N/A