if i was purchasing wireless products, the thing i personally would pay most attention to is the security.. and this product is WPA compatible, which is good! 2nd point is 'performance'. the fact that you can interchange antennas means that you can adapt the device to ur operating environment!
i'd then have a look @ what ur gonna use the device for. being usb, arn't the speeds restricted somehow?!?! thus, if its just for general internet surfing, then i think this would be fine. if u intend on transfering big files all the time, then maybe this is not a good idea. (this is my opinion n e ways)
I think you should wait a little longer because MIMO and 802.11n products have a higher bandwidth and a much wider area of coverage. You might be able to get these new products for around the same price.