I just did some testing with my new RPI gateway with 868mhz RFM69HW and dipole antenna, located at the top floor in my 3 floor house. Walking around with a battery node (also HW, but wire antenna) I tested every corner and floor of the house and the connection is solid everywhere, no need for repeater nodes.
Just for fun I took the node outdoor and was a bit surprised when I discovered that I had quite good connection inside my garage as well, that is some 60m away and with houses in between that I was certain would block the signal (see picture). So, it seems I don't need the RFM95 system I planned for the garage after all! I'm very pleased with the result