You want the 390 Boss in the L/XL size. Way better than the competing Unions.
I've heard the same exact things..i actually had my mind set on the 390 bosses.. but idk what happened lol
Short answer: I've ridden both, liked them both, but LOVE my atlases.
I've heard rome has addressed the "staying strapped in" problem they had on my 2011 390 Bosses, but I just found them to be really "fussy" to set up. The foam padding you can change out is really cool, but was ...not hard, but seemed unneccesarily complicated. More so than Ride's Wedgie and Obviously more than burton's AutoCant.
My Atlases feel at home on my short 149 board and my longer 158 board. They're super easy to set up, wild comfy, easiest to adjust the forward lean (something that's important to me), damp, and just....work. they're my favorite binding of all time. I also like the way the highback is set up. Taller for more response, but flexier at the top so it's still really comfortable.
Thanks for the feedback. I might go to the shop and check the atlases out and see how i like them. Im usually one to go with Union but 2013 Rome Bosses have really good reviews on them