This doorbell arrived today, so I don't know what the long term reliability will be like, but for the price it is very good value for money.
Some wireless doorbells are lacking in volume, but this one is quite audible even through closed doors etc. Some of the tunes are quite cheesy, but then most multiple choice doorbell tunes are. I have chosen the simple 'Ding Dong' tune which is acceptable - for me, anyway.
If you are looking for a cheap, no frills value for money doorbell, then you can't really go wrong with this one.