Has anybody swapped from one to the other? If so was it worth it?

Have not done it. Sorry, I know I'm no help.

Which way are you wanting to go? 6900 to X800 or vice versa? If you're hoping to buy an X800, good luck. They're becoming very hard to find.

Looking at changing from 6800 to x800

I have an x700 pro in my imac. nice, but could be a bit faster.