With respect to Dionyz, there is doubt. I have run a Yamaha receiver in my all-Klipsch system (Forte II mains, Academy, RS-3's and KG-3's) for 7 years. I have also used Sony and Denon with them. In addition, I have used NAD, Pioneer and currently Denon in a 2 channel system with KG-4's. I've owned Klipsch for almost 20 years. I have a lot of experience with various combos.
That said, I have found the Yamaha to be a decent but not perfect match with Klipsch. I used to believe that the Yamaha revealed the details in the music better than Denon but over time I've found it to be a bit too thin sounding. I'm upgrading my receiver this year and looking seriously at the Denon 3808 and Sherwood Newcastle R-972.
Here's my personal list of brands I've looked at and/or demo'd in the past year or so, in the order of personal preference:
Rotel - Sounded absolutely amazing, but feature set is lacking on receivers
NAD - Excellent match with Klipsch but new receivers are out of my price range
Denon 3808 - Excellent feature set, bass a little subdued compared to past receivers.
Sherwood Newcastle - No experience with this brand but the feature set of the upcoming R-972 is beyond amazing. I won't purchase anything until I have a chance to demo this when it's released.
Yamaha - Excellent build quality, apparently a bit warmer than past models
Pioneer Elite - Great warm sound
Finally, I always say this...No matter what any of us say the only thing that matters is how the combo sounds to YOU. Dionyz isn't wrong in his assessment. That's how it sounds to him and there's nothing wrong with that. Others will disagree with him, but we won't be any more right or wrong than he is.