I think that there are a few things that you need to look at when you buy a computer and i am not sure if you really need one for real estate. I would just like to point out why you may not want to have a laptop.
A laptop kills time.
As useful as a computer is it distracts from your message. If you are in a listing appointment instead of looking at the marketing plan the sellers will want to look at the other listings, over, and over, and over again. You want the CMA out there and then close for the listing instead.
With buyers the same thing can happen, there are too many parameters and the buyers will want to see lots of variations on their wants and needs and we all know the emotion of seeing a house in person will overcome almost and objection to so many other considerations that users may think are important