I went and looked at their site. The thing that stood out to me is their claim of the walls being rated to retain heat. Well most of the heat is lost from the open top of the pool. Unless you have a cover no walls will keep the heat in.
They do look easy to build BUT the hardest part of any pool build is the site prep. Once you get the site right the rest will be fairly easy by the looks of it.
There are some playgo builds here. Do a search to find them all. Might be an interesting read for you.
Let us know what you decide to do.
Kim