Originally Posted by Colmike7

Some themes will have options to turn the built in SEO off, but if you keep it on and enable another SEO plugin on top of it, everything can get messed up..

Just look at the code and all options of themes that you use to be sure. I prefer a minimal theme to build on without extras, and avoid bloated themes like Suffusion unless you have time to go through every setting and know what you're doing.