I have manifolds on my 340 in the Cuda and headers on the 440 in the Charger. IMO TTI makes the best headers (quality and fit), so i would lean towards ceramic if you are going this route.
The best thing about headers is they out flow a manifold on most engines, especially if it is not stock and they look awesome. The bad is they are a PITA to take off/on to work on your steering, starter, some plugs are difficult to get to, and its a crap-shoot on fitting a fast ratio arm. Overall they are an extremely tight fit.
Manifolds are great if you just have a mostly stock engine. There is way more room and they look OEM if you are going for that look. The big downside other than performance is if they crack you are basically done and have to go get a new one.
