I tried the demo version of Envox, but I do a lot of weird things when develop, so it was inadequate for my needs. If I was trying to do normal things like create an IVR, it looks as if it would work fine and be extremely easy to develop in.
I don't know about the Telephony Board Simulator. I used Line Simulators to develop against, but never a board simulator. In theory, it should produce the proper events, so it should work. I just hate working with stuff that "should" work.
pansophic