i use a ecotemp L10 and find it perfect for me.i use a high flow and i dont get any pressure issues that i used to get with the L5.even on minimum settings its nice and warm(not too hot to crack glass though used during cold weather).i little turn of the dial and i have very hot water for add ons and dirty first cleans.very happy with it.
i use it all day every day at the moment and costs me around £4 a day in gas.in the warmer weather ill probably just use it for the add ons/dirty jobs.