It hasn't lost sync yet (can monitor that through router) and my ping is really low all of the time, much lower than on Wifi. The powerlines are TP-LINK with the VDSL interference reduction mode switched on. I haven't tried it with it switched off, nor do I intend to.
Since I'm only here temporarily to care for my father who doesn't need internet access in the room with a blackspot when I go back to my own place, I'm reluctant to spend too much money on a solution for what will most likely be only for a short period.
First moment I see any problems i'll re-evaluate, I'm checking the router logs quite often, but I'm not seeing any degrading of performance wherever I am in the house since plugging them in, loss of sync, increased latency or lagging that I've heard others complain about with VDSL and powerline.
This morning I got 76Mbps downstream and 19.1Mbps downstream via Sky router via ethernet and 73.5Mbps downstream and 18.9Mbps downstream via powerline. Yes there is a drop off compared to ethernet downstairs in the office, but it's very minor and vastly superior to the jittery bursting mess I had on Wifi.
Nothing like the Virgin Media connection I had in Dublin mind, but that network over there is supreme.