Having a branded email address differentiates you just a little bit but the one thing it really does is makes you look more credible. If you’re using gmail, hotmail, or yahoo (if you if you’re using yahoo in particular you should really question yourself because they’ve been hacked so many times at this point), you should consider switching. It’s not bad to use those email providers, some people prefer them but if you’re going to market yourself, use your branded email address. It will look like your name at your company name or your brand name .com, .net, .us, .biz, whatever you have.