The Promedias are better and anyone who says otherwise has lead ears. Now if you know me personally you probably know Klipsch is my favorite speaker brand. So you're probably thinking there's some bias going on here. There isn't, I'm perfectly open to finding something that I'll like more, which is why I did the comparison. I got them to about the same volume, subs too, but I just couldn't find out what was great about the Logitech pair. The Klipschs were clearer, they had much better mids (they sounded fuller and more lifelike) and I just liked the Klipsch's sub more. Now the 8" sub on the Logitech pair was a nice touch, and Logitech makes good subs (not great, but good, and I know because at the moment my speakers are some older Logitechs with an 8" sub), but somehow I just much preferred the 6.5" Promedia sub. They were both ported as well. I guess what was nice about the Promedia's was that it was clearer and it mixed with the sats very well. The Logitechs were pretty good too, but I'm just putting that old debate to rest (well actually I'm not since no one will read this, but I'm putting it to rest in my head), and I'm still getting me some Promedias sometime.
Also, I guarantee you that if Klipsch made a big display for their computer speakers like Bose does with there's, Bose would never sell another pair. Just saying, because any good pair of speakers will sound awesome in a display where they're playing sound effect-loaded movies and jazzy music at high volumes.