Link to Basic Owner's Guide
I had been trying to decide between the 73" 638 and 738 2010 models and was having a hard time deciding which one to go with.
The 638 is just a basic TV and had a few hard-to-live-with features for me;
-Video processor not as good as the 738 series. Best to only send it 1080p
-Must use 3D adapter that costs a couple hundred dollars (unless sending
the one format the TV accepts)
-No discrete input codes for universal remotes (I have a harmony one)
The 738 series has;
-A better video processor with advanced calibration settings if needed
-All popular 3D formats where accepted without external equipment
-Discrete input codes for universal remotes
The price on the 738 series was worth it if you plan on doing 3D because you didn't have to buy the adapter. If not doing 3D then you were paying for extra features you may not use, like the internet apps which I do not care for.
The new 640 series seems to be the best of both worlds for ME.
-has advanced picture controls (manual doesn't go into detail)
so I hope the video processor is at least as good as the 738 series
-3D setup same as 738 series
-Discrete input codes for universal remotes is unknown, but I'm hoping
that it's as good as the 738 series
-FOR ME, no extra frills like internet apps. The downside to this is using a
USB drive for firmware updates, but a TV with these features shouldn't need
one very often.
-Has a new cosmetic design which I hope means a better screen mount
because the 73" 638/738 series seemed to have the most geometry issues.
That's my take anyway. Seems like it might be the TV for me. I'm seriously looking forward to seeing some real-life feedback from owners.