well, i don't think that wheather Anathema, Katatonia nor MDB have much in comon in these days. I mean, from the genre and especially from the feeling and atmosphere. MDB and Anathema were put into the same corner in the past: doom. Anathema left, Mdb is still doom. Even in those days they had little in common with the points i mentioned above. Maybe its only the genre the bands are put in, or the past which makes people compare them with each other. I can't say anything about Opeth for i haven't heard enough of them, i just can compare the other 3 ones. I like MDB and Katatonia, in a different way, but none of them can compete with Anathema for myself.
that's just my opinion