Yeah... I'm not running Powerline ethernet anymore... but when I was, I was using SlingLink adapters. What I learned then was that even though SlingLink Turbo adapters were supposed to be backwards compatible... my powerline network didn't like it with mixed devices... so I ultimately had to have all Turbo or all non-Turbo adapters in the system. That problem was uncovered because the 622/722 had slower speed built-in powerline ethernet than did the 922... so when I got my 922, I had to stop using the built-in on my 622 and get a Turbo adapter.
Meanwhile... Wifi has less of those headaches, but I've had miscellaneous issues with cordless phones, neighbor WiFi, the router itself... and of course I have devices capable of b, g, n WiFi so that muddles things.
Everything is easiest if you can have everything at the same level... but either powerline or WiFi allows for a lot more variables than wired ethernet. So I try to wire everything that I can.