I love Powder Blues. If I had to pick one tang, it would be a PBT.
I've had one. I kept him in a 125. Unfortunately, he killed his tankmates over the course of 6 months. I kept him for another 6 months after that, but succumbed to family pressure to have a community of fish, and I traded him in. He was completely content and grew from 2" to 5" in about a year. He was really fat and just picked on the rock and swam back and forth. Ate anything that hit the water including zuchini, lettuce, and boiled carrots. I could hand feed him.
He seemed kinda bored to be honest. If I ever tried another, I would probably go with a huge tank, if I had the money. They love to swim and I would put them in the "open water" category like a Naso. They need to be housed with tough fish IMHO. Big angels, triggers, damsels, etc. When they go on a tear, look out.