Agreed - a laptop you bring with you to use while on vacation will have no problems.
Nobody has even asked me to open my laptop bag after arriving at any of the DR airports I have used.
I have had a few times (not often) when they wanted to look through my actual luggage, but then got waived through without having to pay any fees.
You will have no problem with your laptop. When you fly home, you will do the same thing you normally do at airport security - put the laptop in a separate bucket as it gets scanned with any other carry-on that you have - but no fees.
I believe the other threads were discussing when a person has a laptop shipped to them, because then customs views it as a resale item and wants the taxes.
Wherever you are staying for vacation - ask about internet access - some places have it in every room, some only in the common areas, some places charge extra, some provide it free.