Both are casein protein, but what's the difference between the two?

In terms of real-world functionality very little.

I did some research on this when I was first looking into ordering protein, and found plenty of things that said that there was a difference, but nothing that explained exactly what that difference was. There was just a lot of stuff talking about casein in general, and vague statements about how calcium caseinate was "regarded as the lesser quality of the two."

I just ordered the Micellar Casein to be safe and intended to spend more time figuring out the whole story before my next order, but I got sidetracked.

I'd be curious what Laura from ATW would say as her company sells both products.

Interesting. I guess I have to really look into it before I place my order.

There are claimed differences by those that market the product (Scott Connelly of Met-RX fame for example) but in terms of a real world difference in results there are essentially none.

So it makes no difference which ever one I order?

Micellar casein is more structurally "intact", to put it one way. It's less denatured. Whether or not this affects measurable physical outcomes has not yet been determined by relevant clinical trials (ie, comparing calcium caseinate versus micellar casein on healthy trainees). For right now, it boils down to personal philosophy since we don't have any quantifiable data. This case is very similar to the question of whether/not you'd pay more for whey protein isolate (WPI) as opposed to the cheaper whey protein concentrate (WPC). I definitely notice a difference in visible purity, mixability, and taste superiority of WPI. This has lead me to take the optimistic route of sticking with micellar casein products.

To arrive at casein you subject skim milk to an acidifying process which precipitates the casein fraction out of the milk. A chemical reaction occurs and the casein protein drops to the bottom. The casein is then washed and then mixed with calcium hydroxide in order that it can be soluble.
Micellar Casein is derived another way. It is put through a system of filtration rather that subjected to chemical processes to isolate the protein. Actual powdered micellar casein is isolated to a degree of 92% micel casein and 8% whey.
The argument as to which is a better food is mixed. On the one hand micellar casein has experienced no molecular change and is just isolated micellar casein though it still has an 8% whey residue.
Calcium Caseinate has been subjected to chemical processing but it has no whey residue in its make up. You will notice that per serving you get 3 points more of protein (25 grams) than with the micellar (22 grams). :tu:

Any difference in mixability/taste?

I cannot answer that....but I can guarentee that I will refund if not happy............ I have not tried them both to be able to honestly answer.

:tu:

I've found that in general, protein powders with micellar casein are alot thicker, and fill me up for longer. It would follow that they take longer to digest also.