I also have the expedition asym. It's a pretty good one man shelter that's light, easy to set up and not too expensive. But it has it's quirks, off the top of my head:

Pros:
Light, 2lb 10oz if i remember right.
Easy to set up, just tie to trees.
Fast setup, easier in rain.
Off the ground, don't need to worry about dirt or bugs.
Really comfortable, no rocks, water running in etc.
Can be set for pretty tightly closed or wide open, if the weather's good, roll up the fly.
Condensation in cold weather should roll down the fly
No fiddling with the poles, hooks, stakes, flies of tents.
No people asking to 'borrow' it to change dirty clothes etc.

Cons:
You have to pitch where the trees/poles are. Deserts are not good.
You have to pitch in the direction of trees, may not be best for wind.
The regular fly isn't so good in blown rain, get the bigger one for security.
Can't sit down on the 'floor', it's only really good for sleeping.
No place to put lots of gear inside, it all slides into you.
You still need to carry either a insulating pad or underquilt unless it's really hot and then the mosquitoes will bite you through the fabric.
You will be tempted to fiddle with the tie-outs, treestraps incessantly to get the perfect hang.
Only 1 person at a time, can't invite your 'new special friend.'