SipGate also has automatic topup, we are using it on both our basic accounts.
To the OP, we are using four gigaset handsets paired to an N300 base unit (with answerphone built in). We use SipGate and have a pair of 01 numbers for outside callers and its working great.
The main thing is to look at the call packages, basic rates, features etc... either way whoever you go with I recommend the gigaset units, they work really well in our house (thick walls) and we also have a DECT repeater to increase the range to the other part of the house for the second number, works fine with all VoIP features.
Moorsweb rural wireless broadband
12Mbit down / 7mbit up, great service.
Edited by mrvanx (Thu 24-Mar-16 18:37:40)