I don't have any affiliation with the folks who make this product, but I've found it so useful that I wanted to share my experience with it.
When I got back into watercolor, I painted on watercolor blocks at first. I eventually started using 140 lb. paper, stretching it by stapling it to hardwood-faced plywood that I bought at the lumberyard, cut to size, and finished with polyurethane to prevent the wood from staining the paper. Those boards provided a solid working surface, if a bit heavy. However, removing the staples at the end was a considerable effort, not to mention high risk -- more than once, the little screwdriver I used to pry up the staples slipped and skidded toward my finished painting. And there was the sickening experience of actually having the screwdriver skid *across* one of my paintings, gouging up bits of the image. But the advantages to using stretched paper were enough that I continued using the boards.
This past winter, I bought an Incredible Art Board to take to a workshop and, as a result, will be switching to them for all of my painting. The boards aren't cheap, but they're worth every penny in my opinion. They're lightweight and sturdy and hold the staples firmly in place. More important -- it's SO easy to remove the finished painting. What you see above is an inexpensive plastic palette knife that I use to remove the paper from the board. By simply sliding the knife under the edge of the paper and lifting it up, I am able to free the painting with almost no effort and no worries that I'm going to damage it. The staples lift out with the paper and are easy to remove.
The boards are available in both a full-sheet size and a half-sheet size (both are slightly oversized), but can be cut down with a utility knife -- if you work on quarter sheets for plein air painting, for example. Even if you don't stretch your paper, the boards make a great, lightweight support.