Bras seem to come in all the wrong sizes, whether you are very big breasted or not. Enell has fixed this problem, by having an easy-to-use size chart and more sizes than a normal bra. They have bras that fit women from 32C - 50DDD. However, they also will make custom bras! If there isn't a bra your size, they'll make you one.
They are also very nice if you contact them with questions about sizing.
Enell bras are the best support I have ever seen in bras. There is little-to-no motion at all, even during running or jumping. Through use of both compression and encapsulation, Enell bras are as close as you can come to leaving your chest at home.
There are special instructions for putting it on, though it really doesn't take anymore time and is a lot easier to remove than your average sweaty sports bra. (It uses hooks and eyes, instead of the over-the-head method.) It also feels a little small when you put it on, but adjusts to your size and this is probably what really gives you the added support.
Enell bras are a little odd feeling at first, but after several runs, you start to appreciate the difference. I often forget about having it on at all (because I'm not feeling the normal movement), so I wouldn't say the initial oddness is a problem.
I can move around with out it sliding or chafing. There also are no dig marks on my shoulder after my runs with this bra. I do get dig marks from the chest band though.
More importantly, the Enell bra doesn't restrict my breathing, just the bounce.
This is where Enell bras really fail. They aren't very pretty. I probably wouldn't run in just an Enell bra and shorts, for the sake of my vanity. They seem to be working on this by now offering purple in addition to black, beige, and white bras.
Personally, however, I feel that this is a mere hiccup in an incredibly good bra.