I personally would not recommend this shield. It's a clone of the Asynclabs WiShield. While the libraries are still available through the Asynclabs website there is no support and no development going on.
If a WiFi shield is easy to use depends on what kind of project is going to be implemented.
I believe until the official Arduino WiFi shield is a little more mature in terms of hardware but particularly software it will be more of a hackers item and won't be that easy to use.
If your project is not mobile - but even in that case the following can work - you can simply use a standard Ethehrnet shield and connect (via Ethernet Cable) a little pocket WiFi router to it. I've used a TP-Link TL-WR703n and a TP-Link TL-WR702n and this works very well. It's not more expensive than a WiFi shield and you can use the full functionality of the mature Ethernet library and also use many libraries that depend on the Ethernet library and that would not work with a given WiFi shield without considerable work on the library itself..