Hems, your answer is right here & then some (the link below that is).ÿI was struggling to choose between those two earlier in the year, then the Sony had a storming review.ÿYou do know, that the team had to knock the stars off of several AV amps, right? The Yamaha 3900 and the Pioneer 81. I didn't think I could get any more excited about an AV amp, as I want a single setup solution, for movies and music.
http://www.whathifi.com/Review/Sony-STR-DA5400ES/
With what I know about the 6400 it's got a few more extras... the thing which impressed me the most was a fully custom remote that you could program via the HUD of the amps X-bar/menu display. It looked very user friendly and easy to setup. I would only go for the 6400 if you really want to take advantage of the multi-room features. That is what most of the extras focus on. If you want the AV for one room, the 6400 would have a lot of extra features go to waste. The 6400 is a worlds first dual room something or other to support 1080p and 1080i in two rooms... I think, maybe.
I too was wondering about one or the other, then the 5400 won EISA Reciever of 2009 award & they also said;ÿ
"All in all, this is one of the best performing and versatile HD AV receivers available, regardless of price."ÿ
But then...ÿ
...what hi-fi posted a video review of the Arcam AVR600. The day I watched that video review I must have had 108 battles within my mind, 'Doÿnotÿbuy such a huge, heavy, expensive lump of Arcam (Engineered in UK, made in China) steel.'
I lost.
The words "worth every penny" echoed in my mind. I knew everything else in my setup was out of the amps league; all but for the Arcam DV 139 (also reviewed here). They would look nice together, and it wouldn't be so lonely.
ÿ2nd ever post!ÿ