We started using the Pampers Easy Ups Trainers about four months ago and my toddler and I both love them.  If you have a wiggly toddler always on the go these are great no more fighting to get the tabs latched before they try and make a run for it, and no more naked baby when they undo those tabs.  We have also tried to Huggies Pull Ups and my daughter seems to prefer the Easy Ups.  The site 2T-3T is a size 4.  The only downfall I find is that unlike Pull Ups there are no already attached side tabs so there is no wrapping the diaper up tight if your toddler makes a mistake.