No direct experience, Rach, but when I was doing my CELTA both my tutors - who had DELTAs - advised strongly against doing the intensive version. (Well, perhaps they didn't advise against it so much as suggest that anyone who did it must be mad! They both took the DELTA over 9 mths, on top of a teaching job. (Unfortunately, as I'm finding, you need a DELTA to get a teaching job, in the UK, that is.)
b