I will need a way to connect my Ethernet cable to my rMBP. I know Apple makes a Thunderbolt adapter, but it has pretty poor reviews on the Apple Store website (42 five star ratings but also 30 one star ratings). Tek Republic has a USB 3.0 to Ethernet adapter on Amazon for only $20 and it has mostly five star ratings. Of course, the downside is that it would use one of my two USB ports. Can someone tell me if this is slower than Thunderbolt, or would it not make a difference? Does this seem like a better option, or would I be best taking a gamble with Apple's adapter? Thanks!