Personally I look at it in terms of the audience you are targeting. I first started with my personal twitter handle that covered a vast range of subjects and then found my followers and interest split between entrepreneurship, innovation and cloud computing/big data. As such, I created three twitter handles to address each and manage them in that respect to avoid crossover. For marketing purposes I would attach a different twitter handle for your blog and business to ensure followers remain loyal and interested. Keep your personal twitter handle to cross-pollinate tweets that serve many audiences.