i personally have not treated the PRICE as value. i have done maths on mining costs and also the long term MINIMUM the coin sold for in a period and treated that as the value line
Me neither, although I have to say for practical purposes most of my mind's occupation is with price, since I need to sell my btc or use it to pay for stuff but I get what you mean here.
And that's why I am constantly reminded of how the price was first established, on a cost of generating. I daresay it's super difficult to (accurately) estimate what it costs now but I've always felt that price is a lot higher up than the cost and miners do that so they can weather out the periods when price is below the cost.
So I generally can have an idea about price and cost. Value? That's more philosophical for me =)