I've owned both at one time or another. I still own the Hex, both in the tarp version and the tent version (with beak). It's disadvantage is that it sets up in only one way, but it sets up in that way in no time at all.
Consider getting the Hexamid in the "tent" version, which has the bug netting included as the side wall and floor of the shelter. (Get it with the beak.) Adding an internal bug net makes setup far too complicated, especially in times of bad weather.
I have to disagree with the previous poster about the performance of the Hex in high winds. It's aerodynamic design and 8/9 stakeout points make it extraordinarily effective in the wind -- especially if you set it up with the back of the tent into the wind.
It's more expensive, certainly, but it's incredibly light and well constructed to your specifications by hand by Joe(and his wife?) at zPacks. It's also easy to repair on the fly mailing tape or duct tape sticks to Cuben very well. Also, the bug netting makes a remarkably and surprisingly resilient floor. Any holes in the bug net are easily repaired with a couple of stitches. (I had to do that once because of the ember from a nearby fire. Should have set up farther away.)
During non-bug seasons, I use the Hex tarp. The nice thing about the one-setup design is that it goes up in a minute or two -- and with only one trekking pole. If it's getting dark, you'll appreciate the ease with which it goes up.
You'll have to wait for anything you get from zPacks, but it's certainly worth the wait. Joe at zPacks really seems to treat every order as if it were the only order he has, each in its turn. The guy really cares about his customers.
Good luck. Have fun.