Honestly, it's up to the actual fish. Some get along great, while others attack each other relentlessly. I have had seemingly "reef safe" tangs eat thousand dollar corals before my eyes, and known coral eaters be perfect angels.
That said, tangs do belong in large tanks with plenty of swimming/grazing room. In my experience, they have not done well in small tanks long term.
Some say different body types get along together, while I have seen it go either way.