What's so great about this wireless option? Everyone says it's better than 5100.

If you are concerned about Wifi performance, the 5100 is said to perform a little less than the old 4965AGN card. For improved performance, go with the 5300 (3x3). The 3x3 means that it has three radios and three antennas. The 5300 will outperform the 4965AGN. You will likely need a supporting base station for maximum performance.

The 5100 is 1x2, which is 1 radio, 2 antennas.

I also ordered the 5300 because I think I might be able to swap it for the WiMax card at a later time. From what I understand, WiMax will also require 3 antennas. They might put the 3 antennas in with the 5100, but I didn't want to take a chance.

Strangely enough - the T5300 would not connect in my office. I've had 20 other machines (and my phone) work fine. After poking around - it seemed to be unhappy that a channel was being shared with something down the street. Changing from channel 11 to 10 solved it.

What about the Atheros card? That's supposed to be better than any Intel card, no? It also has 3x3 MIMO I believe!?

No

Cheers,

Bill B.