Bob.. I guess it might be a matter of tastes, I didn't read your post before I placed the order, but I did order the 350s. I auditioned them against the 450s and the Mythos Ones.
I agree the 450s aren't muddy. They do take a lot of the detail off in exchange for a more room filling sound. They are warmer, a little less airy. But after an hour of A/B, I went with the 350s. I just preferred them, but I don't think they are better or worse, just a preference. Another thing to keep in mind is I will be running them through my Arcam AVR250, which has a very smooth and slightly warm sound. I think that will take the slight edge off the 350s and it would probably add too much warmth to the 450s.
I figure its a small investment, if I love them, and want to get something different, I can throw my 350s in another room, and upgrade. But honestly I liked the sound of the 350s a bit better than the 450s, and 10x better than the more than three times as expensive Mythos Ones. And that was listening to the LOTR soundtrack, so go figure.
But honestly, I am now a DefTech owner and a new appreciator (word?) of their products.
As far as the PowerMonitors, I didn't have as much time to audition them, but with my SuperCubeII, I just didn't feel I needed them in the tiny room I have. But they were cool.
I'll post more when I get my new 350s.