I'm disappointed in this forum -- I thought there'd be more info available here. Y'all were scooped by avsforum. The 640 will allegedly retail for $1,200, which is $100 less than the 635. This is very good news. I was worried it would be much more, since the 740 is $2,999 (not $3,499 as mentioned in the original press release). How could the 740 possibly be worth the extra $1,800?
Here's some of the features of 740 over 640:
1. More power (85 vs 75 W)
2. 7.2 Pre-Outs for dual subwoofers
3. Room EQ for Stereo subwoofers for 7.2
4. Upscaling to 1080i through HDMI
5. Incredible activity-based color LCD remote control
6. Zone II Video Out and OSD
7. More powerful TI DSP, higher clock 250-MHZ vs 225-MHZ
8. Better DACs, discrete Analog Devices
Both 740 and 640 can output a 7.1 soundfield from a 5.1 source either through HDMI, S/PDIF or 6 Channel Direct. This is done by taking the L/R side surrounds and then post-processing by either Pro Logic 2x or Logic 7. And outputting L/R side surrounds and L/R rear surrounds for a 7.1 soundfield. Also note that 740/640 incredible quaduple/6-frequency Bass Manager and Room EQ is available as well.
Here's advantages of 640 over 635:
1. 640 has HDMI, 2 In 1 Out
2. 640 has 8 Channel Digitizer for 6/8 Channel Direct Inputs
3. 640 has iPod connection, for charging, audio and control
4. 640 has XM Ready capability
5. 640 has USB input for streaming PC audio and Music Player primary transport controls
I think 640 will be great for my needs. After it's released I think I might be able to get it for $800 by April if I'm patient. Sounds like the release was delayed from Feb to April, but possibly even later