Should timing the time between receiving 2 messages with virtualwire and millis be accurate to 1ms since your measuring from message end to end? I'm 99.99% sure it would be but the other .01% of my tired brain is saying ask anyways...
It depends. I don't know about virtualwire. On some Arduinos, millis() could be off by a couple of milliseconds. micros() might be better if the period between messages is short enough.
micros works fine with my code so I'll probably just end up using that for safe measure and hope for the best unless someone else has ideas.