What is the difference between a PDU and a power strip (both 120V, 15A)?
Solution 1:
In addition to amcnabb's answer, higher-end PDUs (though not the one you linked to) will also give you the possibility of not only monitoring (over the network) the current draw for each socket, but also cutting and restoring power to certain sockets remotely.
Solution 2:
A PDU will mount nicely to a rack, while a power strip is likely to get pushed around. It's mostly a matter of convenience, but in theory a power strip wiggling around could make a safety or reliability issue.
Solution 3:
I found this from APC's FAQs: Using surge strips with APC's Back-UPS and Smart-UPS products. Looks like a PDU is a bit different than a regular power strip.
Surge protectors filter the power for surges and offer EMI/RFI filtering but do not efficiently distribute the power, meaning that some equipment may be deprived of the necessary amperage it requires to run properly causing your attached equipment (computer, monitor, etc) to shutdown or reboot. If you need to supply additional receptacles on the output of your UPS, we recommend using Power Distribution Units (PDU's). PDUs evenly distribute the amperage among the outlets, while the UPS will filter the power and provide surge protection. PDUs use and distribute the available amperage more efficiently, allowing your equipment to receive the best available power to maintain operation.