Easy instructions for accessing OED online have been published in
this list, but I don't wish to draw attention to them again. Anyone
who wants to know the simple trick, please email me.
A supreme advantage of OED online is its integration with HTOED, a
resource arguably even more remarkable than OED itself. This makes it
preferable to all CD-ROM OED versions published so far.
By contrast, HTOED in book form is exceptionally cumbresome to use.
At present, online and book appear to be the only ways HTOED is available.
(I must admit I like having a one-volume Shorter OED handy.)