ZyXEL PLA5205 / Linksys PLE500
This head-to-head pits Linksys' PLE500 Powerline 1-port Gigabit Ethernet Adapter vs. ZyXEL's PLA5205 600 Mbps Powerline Gigabit Ethernet Adapter. Both products are the first to ship using Qualcomm Atheros' QCA7450 / AR1540 HomePlug AV2 chipset announced in October 2012.
Linksys makes the PLE500 available only as part of the two-adapter PLEK500 kit. ZyXEL sells the PLA5205 individually, but also as part of a PLA5205KIT. Both will cost you around $120 for the two-adapter kit and the PLA5205 alone runs $70.
Both products are physically very similar with a single 10/100/1000 Ethernet port on their bottom edge (not visible in the photo below). You can see that both are sized so that they will not block the other outlet in a standard U.S. duplex outlet.
Linksys PLE500 / ZyXEL PLA5205 plugged in
Both have three-prong outlets on their backside. The ground prong isn't just there for safety—it's actually used for signal transmission. This trick is used more in the MIMO form of AV2, which I'll touch upon shortly. Note that despite the U.S. plug, both products are rated from 100 - 240 VAC.
Linksys PLE500 / ZyXEL PLA5205 plug side
Linksys PLE500 ports and indicators
One possible difference is that ZyXEL says that its HomePlug indicator supports the Green / Amber / Red connection quality feature that is standard on "AV 500" devices, as shown in the table taken from its user guide below. Linksys makes no mention of this feature in its documentation.
ZyXEL PLA5205 LEDs
I've never paid much attention to this feature, so plugged one adapter into my office, which is behind a throughput-killing AFCI breaker, and walked another around to various outlets. Both adapters showed a green powerline / HomePlug light, even when plugged into an outlet in my detached garage!