Although I really liked the Sierras...the Towers IMO are the much better all around speaker. More efficent speaker of course making for better dynamics playing louder without much effort...to my ears anyways.
I had asked the question regarding the RAAL vs the NrT dilemma and was told this by a few menbers via PM....if your primary focus is music related material go with the RAAL... otherwise... the NrT is about every bit as good.
They're both voiced similar so they'll integrated well together with great detail making them very revealing speakers....some actually feel that the NrT's giving it's wider dispersion atributes makes for a larger listening soundstage for HT....but if you're primary focus is music oriented the RAAL would be your best bet BUT it will cost you...

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Good luck