No problems so far, answering machine functions correctly and handsets work well in both normal and hands-free modes. I get a bit of an echo when using the handset at the bottom of the garden (20+ meters, through 2 walls), but apart from that remote operation is very good.
The color screen is a bit of a gimmick really - very low resolution so doesn't look all that great (think 1990's mobile phone). Also as other reviewers have noted most of the ringtones are pretty horrific. At present both the base station and the handsets produce different rings for an incoming call, so it's quite a cacophony, but you certainly can't miss it! We need to read the manual more to see if this can be changed.
Apart from those minor issues all other functions are good. Using hands-free combined with mute button worked well for a large conference call taken at home - was able to make my lunch while listening to the blather!