I have at least 20 pairs of sneakers that I use but none of them are as comfortable as this one.  I walk on my treadmill and on occasion, I do aerobics.
First let me say, these are so cool looking.  They have a mesh upper so they are really cool and lightweight.  They have a nice sole so you don't slip and it really gives you great traction.
They do run true to size and I can even put on a light sock with these.
I have all brands but none of them are PUMA and now I actually think I am converted to a PUMA user.  They fit really nice in the toes, not too tight.  Your foot just slips in and the laces are well placed.  i walked the first time for almost an hour and my feet were feeling good.  My back was good too.  These have some kind of support in them that keep you walking up straight, if that makes any sense.
I really love these sneakers.  Not only do they look good but they are very functional and I actually can't wait until tomorrow so I can work out again.
If you're in the market for a great sneaker, and you just can't find one, give these a try.  you really might be surprised.