They should both work fine. Next time do research!
bcm4312 should use b43 as driver and it is capable (I had one card using b43 and it seemed fine). However, the other one uses ath5k and atheros is known to work well (with a few exception though)
bcm4312 should use b43 as driver and it is capable (I had one card using b43 and it seemed fine). However, the other one uses ath5k and atheros is known to work well (with a few exception though)