Before you read on, know that this got rave reviews from all, including our son, who absolutely loved wearing it.  It also made for excellent pictures.  For these reasons, it got a four, though it likely deserved a three.

Having said that, we bought this in the 2-4 toddler size for a slightly-tall two-year-old, and there was no room to spare, especially when we put some pajama-like clothes under the costume for warmth.  The length wasn't the problem.  It was the other dimensions that were pushing it, and he's on the slim side.  The stitching over his back was already coming loose when we put it on the first time, and the velcro holding the neck together of the uniform itself didn't make it through the third wearing (busy Halloween), so a safety pin was needed.  The cape's velcro is about to go, too.

Just an FYI, the picture makes it look like the uniform goes over the shoes, which it does in a way.  The bottom of the feet are open with straps that go under the shoes.  That worked really well, actually, and looked pretty convincing.  It was helpful when we went to a place that required that we take our shoes off.

So, all in all, it's an adorable costume, but don't expect it to last very long.