I think that when you are going to wear just jeans and t-shirt, you'll prefer the 6's size....
That was one of my concerns. Seasonal. It's winter in NY right now. I've got big jacket pockets right now. In the summer, when I've gotten nothing but shorts and a T-shirt on, the Plus would have ended up even more of a pain to carry around.
I'm glad there are 2 choices. I've owned both, and happy that I have. I am a fan of both. If I didn't have kids to feed, I'd probably own both.