VoIP on EDGE

[ixish]

Hi guys,
I was considering getting a data-only plan (http://www.t-mobile.com/shop/Plans/cell-phone-plans-detail.aspx?tp=tb1&rateplan=T-Mobile-Total-Internet) from Tmobile. Since there's little 3G coverage in my area I would be primarily on EDGE for making and receiving calls.

How well do VoIP services work over EDGE (latency/bandwidth)? I haven't really found a consensus about it. There have been good results for fring (http://forum.xda-developers.com/showthread.php?p=1352571)(not on android yet) and some bad (http://forum.xda-developers.com/showthread.php?t=288572)ones. Does it vary on the connection strength? Service? Any help would be appreciated. Thank you.

[stepw]

It's a lottery, you'll have to try for yourself to see what it's like.
There may be location specific issues too, e.g. in strong signal areas you'll have reasonable latency and jitter, in weak signal areas it might be totally unusable. There's plenty of overhead that data network adds.