I'm guessing you haven't actually used one of these units? You'll be lucky to get half of either of those values.
FWIW, note that, unlike the majority of the network equipment industry, $UBNT's throughput numbers are aggregate values (i.e. equal to transmit + receive). 1.2 Gbps in $UBNT-speak, for example, means 600 Mbps transmit and 600 Mbps receive -- whereas an 1 Gbps NIC can transmit 1 Gbps and receive 1 Gbps simultaneously (yet we don't call them 2 Gbps NICs).
FWIW, note that, unlike the majority of the network equipment industry, $UBNT's throughput numbers are aggregate values (i.e. equal to transmit + receive). 1.2 Gbps in $UBNT-speak, for example, means 600 Mbps transmit and 600 Mbps receive -- whereas an 1 Gbps NIC can transmit 1 Gbps and receive 1 Gbps simultaneously (yet we don't call them 2 Gbps NICs).