To answer your original question, I say yes. I hadn't watched much Dr. Who-I can't recall if I had ever seen a full episode of Dr. Who before watching Torchwood. I liked Torchwood quite a bit, particularly the first three seasons. Season Three is called Children of Earth. I'm currently watching Season Four (Miracle Day), but it's not keeping my attention.
From what I remember, Dr. Who did not appear on Torchwood. But his companion Martha Jones was on the show for several episodes, I think in season two. You don't have to have foreknowledge of Jones' role on Who while watching Torchwood but it is a bonus.