Summary: You probably aren't going to see a massive speed boost or anything (Depending on your adapter), but this is very useful for increasing range. I'll likely be buying a second one.
Pros: I bought one of these along with an ASUS N-600 Adapter, and I'm pretty impressed. I saw a great boost in range and stability of my signal. I'm about as far away from my router as I could be, but it holds the connection like a champ. Plus, it looks pretty sweet =)
Cons: I chose to connect it via the base plate, which is a little too light to tilt the antenna at much of an angle without it falling over. I just stuck some duct tape on the bottom. Also, it is a little spendy IMO, but clearly that didn't stop me.
Summary: I haven't been able to tell if these antennas have extended the range of my wireless signal. The range seems to be about the same as before using the antennas but I would have to disconnect these to test that. Maybe later.
Pros: I bought 2 of these to use with my N12 router which I've had for 1 year and they've definitely made the wireless signal stronger. I used to get maybe 2 or 3 bars at certain spots in my house and now I have full bars pretty much everywhere around my house. The price is ok since since these antennas get the job done.
Summary: would not recommend - did not buy at Newegg.
Cons: Did nothing to improve my signal - as a matter of fact, my signal decreased in strength. I returned to the old 3.5DB antennas that came on my router and wireless USB device and the signal got stronger.