The functions of this anwering machine are comprehensive and, largely, well thought-out. The manual - such as it is - is poor. It is necessary to resort to the on-line instructions (so often the case these days) - and these are also unsatisfactory. There's no alternative than to work it out by a process of trial-and-error and intuition! Once this is done, the machine rewards with some innovative and clever features.
Sound quality seems reasonable - but not great - better than the digital recorder built into my DECT phone. The audible 'beep' when a message is waiting is helpful: I don't always remember to look at the display. Silent message recording (i.e. you can choose not to have the message blaring out if you don't want it) is nice. 'VIPs' (eg friends and family) can tap in a code to alert you, so that you can pick up. Not sure how useful this will be.
Lastly: the machine will dial 1471 for every missed call (if you want it to), and replay the caller's number - even if they didn't leave a message: clever (and free).