I think that the most common way to value Bitcoin is like valuing other currency by another currency.
Seeing to it that we all know all the factors that causes or affects supply and demand equilibrium.
Also the time we hold bitcoins. Time is very important factor.
I value bitcoin in way of giving so much importance and time than to the other crypto currency. Bitcoin is my fisrt choice thats why i am closely monitoring price value due to my current investments. I believe that bitcoin future is very bright and the only crypto currency that offers a future prosperity because of continous success in terms of price value.