I've used Sundeala on my layout but would consider other options in the future. I made the mistake of storing my Sundeala for several months before constructing the frames. When it came to screwing them down, the boards had warped. I've levelled the surface with a surform where necessary, but this was a lot of extra work. If the Sundeala is of good quality and is fastened to your frames in a flat state, it should be OK. Alternatively, I don't think you would go far wrong using a plywood base with a cork layer for the trackbed. You would still need to support the plywood with a wooden frame, but this need not be as intricate as one for Sundeala.
Regards
