I haven't done the exhaustive testing that Alec has but am very impressed with my 1st TalkPlus call tonight to my sister's 416 area code cellphone using the TalkPlus beta. More later.
1. Allows you to attach more than one phone line to your mobile phone. There's no need to have multiple SIMs or accounts. Rather, TalkPlus lets you simply add phone lines — like your office line, your personal mobile phone, and your home phone — to your handset. You can also add virtual lines, which simply terminate on the cellular handset. From that point forward, any calls you make can be made presenting the caller ID that you choose.
2. Allows you to save money on your phone bill by making every cellular call into a local call. That means I can call friends on the west coast, or in Europe, but only pay for local Ottawa minutes (plus a few pennies per minute to TalkPlus). With the confusing array of cellular options available, this means a radical simplification for many of us.
3. Host conference calls from the handset. Simply select the people you wish to have join the call, and it will call them and bring them into the call, using the same low TalkPlus rates.