Power LAN can work for years without any problems and the slightest change in the environment (e.g. a disturbing device in the neighbor’s room) can bring the fun to an abrupt end.
If you have an IB2 and set it up optimally, you should still have good reception on the other floor. Depending on the environment, this can also be problematic; floor heating, for example, can be a “killer” for WiFi. In this case, it is recommended to use a WB on the other floor and this brings us back to the topic of Ethernet LAN to connect the WB to the IB.