The Ahead teardrop shape and excellent zip configuration, is so simple but amazingly effective.
I replaced a very cheap (but functioning) bag with this one, and the difference is amazing... no longer am I holding the drum and shaking it to try to get the bag off, or equally running my thumbs around the edge to find which bit of metalwork its snagged on this time.
Its such a little thing, but when you have a full set of mics, mic stands, mixer, cymbals, stands, etc to pack away at a gig, every little helps. Having drums that go smoothly in to the cases they're meant for is very very nice.
The build quality seems fantastic, with a chunkiness to the bags that reassures you of a high-end product.
Overall - I can't fault these at all, and would recommend.
I am considering replacing some of my other kit bags/cases with these as taking any of those kits on gigs is now a noticeable bigger headache.