You're talking about two very good speaker brands. I think the worn out advice "let you ears tell you" might have to be applicable in this case.
I have the Atlantic Technology 370THX set, almost identical to the 450 set without the nice finish. When buying them, I had listened to the comparable Paradigm set(don't recall the model). For my ears, the Paradigm was just a bit on the etheral side, for want of a better description. Or maybe I could say a bit "soft or fuzzy". Your ears and surroundings might tell you something completely different.
I have had the Atlantic Tech. 450's in my HT setup for a couple of years. They sound excellent in my opinion and very happy with the quality. 2 weeks ago I went from rear projection to a Sharp 9000 front projector. There is one thing that bugs me about the 450's. The L & R front floor standing units reflect light/glare on the glossy sides of the speakers from the screen wall. I am currently working on a masking system that might take care of this, and I don't want to move my speakers further away from my optimum, so like I said it just bugs me. If you don't have to set them within ~8-12 inches from the sides and in front of your screen, you should have no problems. I have heard that the 370's with the flat finish sound as good as the 450's and might not have the reflective glare problem. Just a thought. Check the specs on the 350's and listen for yourself.
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