We have one of these at home, and it's a really nice bit of kit. Makes it easy to make or receive calls without disturbing someone else watching TV (main reason why my wife and I bought it was so we wouldn't disturb each other's TV viewing).
They're trying to be like a mobile phone, but the "Send" button is in the wrong place, if you know what I mean, compared to a mobile. My mum has problems using it when they come to visit, even though she has a mobile.
We've still got the original batteries in ours, which are quite quick to charge, depending on how long you've been talking, and the sound quality is really good - however, if there is any noise on the line, then that'll come through a bit louder than than on a regular phone.
When I went away earlier this year, I switched the handset off and left the base unplugged: when I came back, all I had to do was let the base station charge the handset - it had kept all the settings and numbers, but was down to 1/3 charge.
There's a wide range of menus, options and options, and it's caller display ready, which is very handy for us as we can see when there are withheld numbers calling or people we know who's numbers are in the phone's memory.
One complaint is when adding/editing entries in the phone's memory: there doesn't seem to be a space character supported or, if there is, it's very difficult to find.
I'll give it a 1/5 for update possibilities as I don't know if there are any at all.