For our comfort, either idea is far better than using the mat on the floor. But for the boys, the home-made frugal one works much better.
What will we do next time? Definitely take the plywood and buckets (maybe with a sheet of foam from Walmart for that luxury feeling!). It is nicer for the boys to have a little more wiggle room. Besides they'll probably go and grow over the winter and need the space even more!