It depends on how much Hebrew you're doing. If it's confined to the Hebrew Bible, HALOT would suffice. If you're interested in Ben Sira and the inscriptions and the DSS, CDCH covers that, too.
However, even if you're not interested in a larger corpus than the Hebrew Bible, CDCH is still useful in showing other word uses beyond the Bible per se--and all of the examples are translated into English, too. So there's benefit to using it even if you don't ever read any Hebrew inscriptions.
DCH and CDCH also have word frequency counts, which I don't believe HALOT has. (Others will correct me if I'm wrong.)
I'm sure others can weigh in on the content of each dictionary more specifically. The real comparison, though, would be between the full DCH (not concise) and HALOT.
UPDATE: comparable (in terms of depth) to the Concise DCH is Holladay's Concise HALOT, which is not available in Accordance.
Edited by Abram K-J, 19 February 2014 - 09:37 AM.
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