750 vs 800 vs 850

A lesser lofting down is just that.

Why should there be any difference in fill?
It's more a weight issue in price than durability.

Lower fill down is supposed to hold up better when wet

Lower fill down will more easily leak through fabric?

I was in the same boat. I went with the 750. Nikwax has a wash in down proof http://www.nikwax-usa.com/en-us/products/productdetail.php?productid=269&itemid=-1&fabricid=-1

Someone gave me the EE 750 for xmas

It lofts just fine … Is it a tad heavier and slightly less compressible, probably

Do i care when theres a 200$ price difference? … Mot one whit

;)

You will need to investigate this, but I have noticed that the lower fill power downs are often Duck down, while the higher power fills are almost exclusively Goose down. It is my understanding that, aside from the weight differences, Goose is superior in terms of performance and longevity.

When comparing items using different fill power downs, side by side in the store, the difference in compressibility, softness and just the way an item "handles" is clearly superior with the high fill power Goose down. Anecdotally, I have read reports from owners of lower fill power Duck down items complaining of odd smells arising from getting damp in the field.

I personally do not have any experience with the lower fill power downs (other than inspection in the store), having always opted for the "upgrade". My WM Megalite is 9 years old and the most beautifully constructed, highly functioning piece of equipment I have ever owned…today it remains exactly as it was the day it was new. My MontBell UL 800 fill Goose parka is likewise a beauty and a joy.

EE does state that the 750 is duck down, if I'm not mistaken. But I don't think the species matters. For many years the best down available was Eider down (ducks). A cubic inch is a cubic inch and an ounce is an ounce. Smell might be different, but any wet down bag smells funny to me – but who's gonna get it wet :)

750 goose or duck … i cant tell the difference

now if yr talking about the cheap 400 fill duck thats 50% feathers that might be a different story

as to longevity … it all depends how much you use the gear on a daily basis …

my view is that the higher fill power down is subject to faster collapse especially from humidity, but also from body oils and general use … which means youll need to wash it more

and on UL down jackets anyways, you wont get 20+ years of use if you use it frequently, the thin shell will go way before then

;)