Very good
This works very well for my extremely deaf mother-in-law who's not got great eyesight either.  Pretty simple to use.  Also works solely off the phone jack, no electricity supply needed.  This has proved very useful for her - both in power cuts and when traveling (she takes it with her, even to the Philippines!).  A little loud and buzzy for use by the non-hard-of-hearing, but not a problem.
Rating: 4 stars