Not yet, but my micro-shelled Flex with the twin driver is shipping tomorrow. So I'll have that soon. I assume the dynamic driver model would be the most dependent on shell size, where the BA models would not change much between them.
As far as comfort - I find the medium shell nice and quick for insertion/removal. It might be more comfy for some ears, but a good fitting full shell would probably be just as comfy (and more secure for workouts or things like that).
I have a different custom in a micro-shell, and it is supremely comfortable. That one is silicone but I suspect acrylic will be similarly nice. Since it only goes into the canal, you can get a deep insertion.
Edited by project86 - 9/24/12 at 3:33pm