If you have an option for moca versus powerline, I would definitely go that route instead. Even the older moca is 270Mbps--which blows away the top potential performance of even the highest end powerline units, and the newest moca 2.5 is a true 2.5Gbps network, which is essentially full bandwidth wired ethernet.
Now, if cost is of some concern, then you can get away with using av500 powerlines as most televisions still only have a 100Mbps nic and don't use more than 40Mbps no matter what they are doing--well within what good av500 powerlines can do. Plus, because av500 are old, you should be able to find them used for dirt cheap and essentially upgrade to a 'wired' infrastructure for a fraction of new powerlines or moca.