Swim belts

since no one else replied, I'll add my beginner .02...  I have the TYR waist belt and sometimes use it at home when I can't get access to a real pool.  It works well for me, but it does mess with my breathing a bit.  Since there is no forward motion, the pocket of air is not where it should be.  As I'm becoming a better swimmer, and lifting less to breathe, it's more of a problem.  At first I swam fine with it, but now I find breathing (and having to lift further) is messing up my stroke a bit.  My solution is to wear a snorkle and work on other parts of my swimming form while using the belt.  It's a solid workout, and I can focus on little things like hand entry and pull motion instead of breathing.