I love these Contigo travel mugs.  They do not seem to leak once they are locked (I have found they sometimes do but not often enough that it is a problem.  They keep your drinks hot for several hours which I especially enjoy.  My only issue with this is that despite me hand washing this and caring for it, the paint begins to peel off at the top (by where the lid goes on).  I have bought 3 of these and find that no matter what, they begin peeling which then look cheap.