To help all those who find themselves faced with this question, I wanted to provide you side to side comparisons of the options.
As you can see there is a definite gauge difference in the regular version and HD cable
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Not to mention the additional length definitely makes it nicer as draping the cord over your shoulder alone will take-up several feet of cable
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In my opinion, the HD cable is what you want as the standard version almost feels like a cheap alternative to what was originally designed for the unit. By that I mean it is my opinion that whatever engineer designed this piece originally had intended for the power cord to be the thicker gauge (but maybe not that exact length) as it feels more substantial and in line with the perceived quality of the tool. The thinner gauge cable just feels inadequate.
Doesn't the thicker cable just appear to fit better.
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All in all though, once you get past the cable, it is all the same. I have taken both apart and beyond the cable the devices are exact twins in every regard.
If I were you, you've come so far as prepping yourself to spend the money, go the extra $15 and you won't regret it.
*note* - There is a color difference in the shade of red, but I think that is simply due to whoever dyed the plastic that day on the assembly line as it clearly does not differentiate in any way.