What are the advantages of using the 5GHz band vs. 2.4GHz?
All 5GHz channels do not overlap, which means that all channels can be used. The 2.4GHz band has effectively only three non-overlapping channels (1, 6, 11).
The 2.4GHz band is extremely crowded, both due to the overlapping channel issue and its use by cordless phones, baby monitors, etc. Overcrowding makes 802.11b/g WLANs unusable in some locations.