One difference is you will never get the same high ABV, that the "D" process gets. I have never made an Eis style beer, so I can't comment on that. I have made many batches of freeze concentrated hard cider, aka Apple Jack. Some people put their hard cider into an open bucket in the freezer and scoop the ice out as it forms, and some put into bottles. I am a bottle guy myself, I wait until the bottle is relatively frozen, and turn the bottle upside down in a pitcher, and let it go until the ice has changed color. I learned the ice still has some alcohol left in it, so I let the ice completely melt and put the bottle back in the freezer to give it one more try.
AJ that is a little sweet, to me anyway, tastes better. I have two pint bottles, aging. Yes, it does age as time goes by, and I have two-one pint bottles stashed. A couple of weeks ago, my wife and I tasted a little AJ from one of the two bottles that were put away in September 2013, and we were pleasantly surprised by how much smoother it had become. What that boils down to is, one of the bottles goes into a cool, dark place for long term aging, and the other one will get killed off during the next family holiday party. I can't really explain why the contents left in the ice seems to be harsh tasting and cloudy.
