I purchased this for my Lenovo Helix. Some comments on here I thought I would clear up.
First, there are no drivers available for windows 7. It does not work on my windows 7 laptop. It is plug and play as they advertise on my Windows 8 Pro Tablet.
Next, Performance did see a marked improvement. Speed was faster according to several metrics when testing at home, and I was able to see 4x as many signals around me as I could before.
Lastly, on it only being B, G, N. This isn't meant for use at home or office. If you are in those locations and using a 5Ghz connection there are other solutions that are better for getting performance boosts, that should be focused on the AP. This is for when you are travelling, RV parks, Hotels, Airports, Coffee Shops. Places where there are often AP's that are down or for those that you have accounts to like Boingo, are too low to really use. Those folks won't be upgrading their equipment to 802.11ac anytime soon.
For 60 bucks this thing is a solid deal for what it provides. A sizable boost in range and power for public wifi hotspots.