Also, the logic of directly tying valuations of a private company to the only public direct competitor in the space is flawed (analysis don't use GOOG,MSFT for this). Using the current logic; if Dropbox (private) beats the crap out of Box (public), this would result in reduced growth and reduced quarterly numbers for Box. However, Box's numbers are then used as indicators/benchmarks for the cloud storage space, and then used to price Dropbox.
When you look at Box's valuation, you should be aware that the price is partially because of risk/competition from Dropbox. How much of the price? I have no idea.
* Full disclosure I am an ex-Dropbox employee.