I have used Duralast brake shoes and parts like that on my driver cars, but for suspension parts, I personally think it is worth the extra bother to hunt down the Moog. I am also picky about bearings, and will pay extra to get Timken made in the USA bearings. Spicer heavy duty U joints are also worth the hassle to find.
I guess it all depends on whether or not you can return the stuff you bought. If you can, I would. If you can't I don't think the Duralast parts will make your car unsafe, but I personally prefer Moog.
I have a new stock steering box on my car now, but plan to swap it out for a Firm Feel power steering box.
http://www.firmfeel.com/powerst_abe.htmI have heard really good things about them and would like to actually get a little feedback from my steering.