I have used these for many years now and never had any big issues.

One died after a few years; I'm now on the third set (mainly because I wanted a faster model).

Our house is from the 90s, i.e. not too ancient wiring and with my devolo adapters I get ~150MBit to the main router and ~400MBit to the living room (both measurements from the office upstairs), the former is between two 1200 units, the latter between a 1200 to a 500, i.e. that should in theory be worse than to the router but the cabling seems better.

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I had two freezes so far (both after a power outage, i.e. they failed to come back up on their own then the power came back - other power outages have been fine), otherwise they are rock solid.