No experience with the Hackzall, but I generally despise battery-powered tools. :thumbdn:
A corded reciprocating saw from DeWalt costs less, lasts longer, and works better.
If you're going to use it every day and it's a tax write-off from your job, a Milwaukee corded Sawzall is even better than DeWalt but costs more. Makita power tools are probably in-between DeWalt and Milwaukee. Any of the three are better than battery tools.
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If I were to buy battery-powered tools, I would only consider 18v models. That's the conclusion I've reached after years of buying and using battery-powered tools on the job.