Yes, like others here I am surprised and absolutely delighted to find that the Mapco site is up and running again. It really is the most superlative resource, and I have used it in innumerable research projects. I am deeply grateful to the owner for creating it in the first place, for adding to it so energetically over the years, and now for bringing it back to us after a deeply depressing absence.
Its free access has been a joy, of course, but perhaps we are not being realistic. I, for one, would be happy to subscribe to it, assuming the cost is low. Perhaps the model of the IHR/Univ of London's excellent British History Online website is one to consider: some maps could be free, but a premium subscription - say £30 p.a. - could give access to the full range.
Meanwhile I am off there now to make a donation: it is richly deserved.