I purchased the 42mm Moko Strap in Midnight Blue. Its extremely close to an OEM Apple strap, perfect replacement for someone not wanting to spend the full price on a real one. I haven't had a chance to personally test this long term, but it appears I received a perfectly working band with no defects. I would definitely recommend this band to someone not looking to spend the $49 for a real fluoroelastomer one. I think for its retail price and level of quality, its a perfect substitute. Things to note or consider:
1.) There is an obvious texture difference between the Apple brand fluoroelastomer band and these which are silicone. The Moko silicone band tends to be a dust magnet due to this.
2.) There is some leftover mold flashing on the edges of the band. Barely noticeable by itself, but when held side by side with an OEM Apple strap, its definitely there.
3.) It seems to be a true 1:1 replica of the Apple band. The dimensions and sizes all appear to be exact when compared to the OEM band.
4.) Depending how you insert the band, there is an extremely small amount of the band that protrudes from the side of the watch where it snaps in. Its not perfectly flush like the OEM band is. This isn't a deal breaker, as most aftermarket bands and adapters have this issue. Make sure you insert the band properly to ensure it sits almost perfectly flush.
5.) Some people have noted these bands are thinner that the OEM Apple bands. I haven't measured it with a caliper, but it appears to be the same thickness. I think the material its made from gives it a thinner feel than it really is.