I have an Alchemist. I've been using it mostly as a commuter pack, because the same clever setup that enables it to expand to a 55L pack also happens to work really nicely for carrying a tripod while still keeping the top closed. I can pack everything I need to shoot a short film with sync sound, including a 3-point light kit and a 15" shotgun mike in this thing and carry it around town on my bike.
My only concern is that in spite of using it in mild situations, i.e. no mountaineering or even backpacking (I used my McHale for the Mount Rainier summit trip and the week in the Glacier Peak Wilderness), the haul loop came off on one side and there's a small gap in a seam where the stitching is coming loose.
I'm hoping that this isn't an endemic problem, because other than the two spots where the stitching is coming apart, I think it's a great pack, especially for the price. The fabrics themselves are quite burly, so I'm going to pay Eddie Bauer a visit soon and see about an exchange.