If you are only going to Vero, West Palm is slightly more convenient but not a tremendous difference. Whichever airport gives you the best price/flight times. It's not that big a difference.
Be sure to factor in the cost of car rental as well. Rates can vary by location depending on availability (supply and demand again), so comparing cost of airfare alone may not give you the entire picture.
We usually find that flights to Orlando are cheaper than West Palm. Rental cars are cheaper, too, and more choices of rental car companies are available. Besides, if you fly in to Orlando, you can always stop in and say Hi! to Mickey....