The length required to connect the two buildings together using CAT 5 patch cable would most likely result in weakening signal. Cat 5 has a maximum cable length of 100m before the signal begins to weaken as well as it being susceptible to eavesdropping which makes security a concern. If we went with the fiber optic cable instead it has a maximum cable length of 2km before weakening signal. It is not susceptible to eavesdropping and its bandwidth is upwards of 10Gbps. It may be more expensive but fiber optic cabling gives you security with the high bandwidth possibility.
With the new NICs you are getting more reliability because of better collision detection which causes networks to perform faster with better data transfer. With these higher data rates and reliable data transfer the network performs better and more things can get done with the business being conducted. The cons are obviously them not being compatible with the existing NICs. This means you have would have to update the other equipment to be up to date with the SuperNICs costing money and resources. Switching would affect the existing network by increasing speed and performance after everything is updated to be compatible with the new NICs. The layers like Network and Transport would be affected because the NICs handle receiving frames and sending them back out to where they need to go. They handle flow control and packet inspection. These layers would need to be reconfigured to make everything compatible to the upgraded NICs.
The white space might provide more reliable internet with less interference. Wireless networking companies may be excited because it could provide a way to sell internet to more people that is more reliable than 2.4 GHz or wi-fi since more channels would allow less interference. It would provide more channels for people accessing a network to use which would be useful since computers are in high demand, and improved internet functionality is always appealing. Television companies may not be happy with this decision because it limits their ability for station expansion and personal later use.