If you're gonna use the thing all day, every day, then maybe a cordless is ok. If you're gonna regularily use it a long ways from outlets or "on the go", then maybe a cordless is a good idea. But, cordless tool in general suffer from a serious problem: batteries.
If you charge it and put it away, the batteries will self discharge in a week or two and be weakened in the process. Then, when you want to use it, you'll have to wait at least a few hours for them to charge.
If you keep it constantly on the charger, aside from taking up a plug, and bench space and collecting dust, that's bad for the batteries (I don't care what the manufacturer tells you, constant charging of most rechargeable batteries weakens them).
If you use it a bit, but don't run the batteries down completely, and then recharge it, that'll weaken the batteries.
Unless you use the thing constantly such that you do cycle the batteries frequently, or unless you absolutely need cordless, always go with corded power tools.
Then, buy a 100' heavy-duty, 3-wire extension cord and one of those reel things to keep it neatly stored on.
You'll be happy with this combination.
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Chuck
Balisongs -- because it don't mean a thing if it ain't got that swing!
http://www.balisongcollector.com