I don't think I can begin to do the Decca justice, but I'm sure the wonder of th internet will enable you to find some articles to help.
My vague recollection was of a very open and forward sound giving vocals great presence, perhaps a little like horn loudspeakers. Heavy though, so need a matched arm otherwise tracking will be dreadful, and not really comparable to anything contemporary. A bit like asking how does a log fire compare with oil and gas boilers!