That part is the same... ATX is ATX, 12volt. Someone just didn't put it in the spec sheet for the one PSU.
The decision is yours, they both will work the same, again it is the cost. This is all IMO only.
Oh wait, WTF did I do? I was looking at your links again and this whole time I was talking about your #4 and not #2, when comparing my choice to yours... Why didn't you say something you shit? Sorry, to much computer screen time yesterday.
In any case... This has some points to it.
yours...
+3.3V@30A;+5V@30A;+12V1@18A;+12V2@18A;-12V@0.5A; +5VSB@3.0AMine...
+3.3V@24A,+5V@24A,+12V1@17A,+12V2@17A,-12V@0.8A, +5VSB@2.5AWhen talking about amp output, your choice has mine beat.
Again I think you will be fine with one or the other. BUT where is the warranty specs for yours?
Maybe look at the reviews on NewEgg and let that help you?
Yours 40
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16817189014Mine 185
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16817371007