We mostly do residential work and its been good for us. What is your background? I know residential is "easy", but if you have primarily industrial experience, it may be a different world for you. Our service call work comes 100% from referral. People know we come in and do a clean, neat job. I've seen commercial guys go in a house and do $1000 damage to a ceiling to add lights that we could've done with no damage.
My point is just to do what you know, if it's residential, then that's your answer.
Residenial new work can also pay good, but you can lose money if not carefull and fast. It will pay much less than commercial, but cost you less also.