My main reason for using Fring is so that I can use it with Skype and SkypeOut to landlines.
I called Australia and spoke for 2 minutes. Call quality is excellent (over an EDGE connection), although there is a slight delay is audio at times.
Wow - now I can make international calls at SkypeOut rates (and CellC data rates) from my handset.
Interesting point Kro but, short of them actively reading packet headers as they move across their network how are they going to see WHAT you're doing with your 3G/GPRS/EDGE being as data is, or should be, data from their point of view. And if they ARE sniffing/trapping for what it is you may be doing, surely there are (invasion of) customer privacy issues in which WE should be rather more interested?
I have been using Fring for a couple of weeks now - call quality seems to have improved, although there is slight a very slight lag - not sure if this is from Fring, or because I can only use EDGE on CellC and not 3G.
I have tried iSkoot, but am unable to place a call - not sure why, so I can't compare.