About the same? No 60P, no IPB, mediocre sync for display filters. 4 year old technology (550D/500D level).
When I turn of GD do I lose the chance of pink or corrupted frames?
It should, works fine on the 50D.
Also isn't this just an undeveloped version of ML
Nope, 5DII was flagship for a long time. Its about as developed as they get. 50D was under-developed and I think its up to 5DII now. It will split the files, true.. the splitting is annoying though and you have to copy all files over and then combine them together so you're using 2x the disk space for a little bit.
Mainly its a lateral move, I'd get both if anything or just get 5DIII. I'd consider a 50D but its not full frame. 6D and 5DII are about the same price on ebay.
From recording both 50D and 6D the few pixels here or there doesn't make THAT much of a difference. The 6D file sizes are more manageable and look pretty darn similar after up-scaling. You're also only getting ~15 minutes of video on a 64gb $100+ CF card. 6D media is 1/2 price.
If raw is your only criteria then yea, 5DII will record larger longer.