The questions you are asking really boil down to a personal preference. Here are some links with different comparisons for you to take a look at and see how others respond to the differences from machine to machine.
So You Think You Want A Tablet PC.
Spy vs. Spy
I am an M200 owner and love the higher resolution. I've been spoiled by it and couldn't see myself going back to a lower res machine. It is very easy for me to write notes on whether I am creating the note from scratch or annotating or margin notating something pre-existing.
I'm also happy with the M200's size which is smaller than your friends 14" tablet. Very portable for my needs.
The optical drive issue is a good one and I think it, along with viewing angles and screen resolution will probably be one of the things that push the market forward. Although I don't do a lot of this there are programs (Daemon Tools, Alcohol, etc..) that will allow you to set up an emulator and run cd's from an image. I guess a lot of that depends on the program and its requirements.