I like the standard. You get an extra foot per side of coverage for only a couple more ounces. But on the AT you have a nice backup plan of staying in a shelter if say windblown rain occurs. I've only seen the micro and it was plenty good enough coverage except for bad wind blown rain, in that situation I'd imagine the standard would have the same issues as well. If it doesn't work for ya, you can always have a bigger back up one mailed to you.
I really want a micro as well.