I worked with both the paper version and the LPC concept on the A320. For my person I definetly prefere the LPC.
To eliminate the booting problem of the laptop or equivalent computer, they must be operative during the entire flight, but may be in a standby mode wich allows a very quick access to the data required within only a couple of seconds.
If the computer is running you have quick access to all required parts of the FCOM and there are a lot of links within the A&E procedures for example.
Its right that we as pilots must know how to operate these tools but if you are trained I think it's very easy and simple and quite fast.