Another potential advantage would be if you can offload some of your cell minutes to VoIP (whether at home or via Softphone). I get that benefit at home simply with the VoIP handsets. You could get an even bigger offload effect if you are making a lot of cell calls while sitting in a hotel room on the road.
After getting VoIP hooked up, I was able to drop two notches down on my monthly cell plan, saving $37/month. A month or two from now I'll probably drop another notch saving another $15. For now, I'm taking it one step at a time: I want the savings, but not at the expense of having to become anal about watching our family's wireless usage.
Perhaps you'll be able to decrease your 2 wireless phones' "huge" amounts of minutes to "large" amounts of minutes.
