Just out of curiosity, and in light of the credit crunch and failing world currencies, I decided to try and unravel and compare the tariffs of three of the major internet call companies.
As I live in the UK and the bulk of my calls are within the UK to landlines and mobiles I have chosen that to be my yardstick to ascertain the cost per minute.
As you will see, Skype has the edge on landline calls whilst Truphone is just better on mobile calls. However it is Gizmo that stands out as being by far the most expensive for mobile calls.
(I used an exchange rate of �1 = $1.4633c to convert Gizmo's $ rates)
Company UK landline UK mobile
Gizmo �0.02734p �0.28702p
Skype �0.014p �0.166p
Truphone �0.03p �0.15p
I know that calls between, say, Truphone to Truphone are free but to be honest, very few people have VoIP on their phones.
I have all of the above installed on my phone plus Tivi and Fring.
In my experience I find that both Truphone and Gizmo are the easiest to use and integrate well on both my N95 and N95 8GB as well as offering very clear call quality through wifi and 3G. Whilst Fring offers a whole host of features, such as MSN, Yahoo, Facebook etc: I find it just that bit more cumbersome to use and the call quality is not as good.
To achieve a totally FREE call and receive service on VoIP both parties should have the same VoIP installed on their phone and be connected via wifi. The next best thing is to be connected to 3G, both Truphone and Gizmo seem to do this seamlessly if wifi is not available, although this does mean that you use a small amount of data (but far less than the cost of a call in the UK) and an unlimited data plan is a good idea.
Where VoIP really comes into its own is if you are calling abroad as it can cut call costs by tenfold.
I am at present looking at video calling over VoIP and to this end have installed Tivi but have yet to use it.
I would welcome any thoughts, comments or experiences of VoIP calling that you may have.