I have been using a L5 for years now,bought 2 ,one as a back up.Its still in the loft lol.
Thing I don't like about using these is the 20 min cut out timerand the fact I have to return waterback to the tank to get my waterflow down ,as I don't use a very high flow rate.Where I do this shutting of the pole tap does not stop the pump as it still pumping back to the tank , so my heater goes out every 20 minutes.
Apart from that Hot is very nice to use in the winter .