Thanks Lyqtix, I have done that and that's where I got my questions from.
Some examples...
They don't come out and say, "While of the same line for this year, the 638 has inferior internal processing..." They say the 638 has Plush 1080p video processing while saying the 838/738 has Plush 1080p 5GB 12-Bit video processing"...
I still don't know what "step up" means that they list for the 738 and 838...
They call the 838 and 738 "3DTV" while calling the 638 "3D Ready" - not sure what that implies...
The 838 has "Dark Detailer" - have no idea what that really is and I probably won't use it anyway...
The 838 offers bluetooth audio streaming, which is worthless to me...
The 838 has side inputs... That could come in handy, but I wish they were on the front behind a panel...
The 738 and 838 both say "universal" remotes, but the 838 lists IR Learning under user controls...
They just describe things differently, which leaves one to wonder... and why I ask here in the experts playground.