I'm also a big Lululemon fan.Athleta being a close second.I wear my leggings out to run errands on the weekends. I do get some weird looks. Like a previous post stated, "it's as close as you can get to sticking your toe out of the closet".
The difference I noticed between mens and women's is the butt in women's has a seam and mens typically don't.
I love the definition in the butt! So I would never wear mens.