I already own BT diverse 4010 and a power cut "fried" our existing master base unit. Buying this unit means I not only have this phone but two others restored for use. It is a good set because you don't need any wiring around the house as they're all radio linked, just link the master into the one phone socket and that's all.
These phones are superb. I've used them for many years, there range and sound quality are near perfect. If you can pick them up for the right price (they are getting more expensive as they get rarer) definately do so.