No, no - Don't limit yourself.
I have been installing the professional Philips DVD 175 which has as one of the major features RS-232 control. They advertise it all over their site and tout it as one of the BIG features of the player.
Then they don't give out the RS-232 code to actually control it. Not in their 'professional' manual, not online, and NOT ONE CUSTOMER SERVICE NUMBER! It is unbelievable how anti-customer anti-installer anti-human that company is. I finally found a number on their website and it put me into VOICE MAIL! WTF!!!
Nope, Denon just came out with a new 232 controlled DVD player in their pro line up. Looks like the way to go.