So the first one seems to be a PCMCIA 802.11 b/g/n 2T 3R but what about the chipset and the TX / Rx Power? And the second one is a USB 802.11 b/g/n but still nothing about the chipset or the transmit power or sensitivity. You should probably make a search to see if you can have more informations about this stuff.
Here are some nice 802.11 b/g/n USB highpower wifi cards with more specs:
-Alfa 802.11 b/g/n 2000 mW
-Skyvertex 802.11 b/g/n 1000 mW
What do you mean when you ask "working with BackTrack 4? You need to know that there are still some problems to use 802.11 n cards for injection, so in managed mode it will be ok but if you need to make some tests with Airodump-ng and Aireplay-ng you should get a standard 802.11 b/g card which will work better.
You need to tell us what you want to do with your new wifi card, and what are your needs.