I have a set of FX armor and have been in the 501st since 2007. It works well, but the first thing to be changed should be the helmet. It wasn't called the bobblehead kit for nothing.
If you plan on doing a lot of troops with kids, then this kit is fine. In all the years I've been at troops with a bunch of kids not once have I had them say that my armor is not screen accurate. They don't care. All they see, especially if it's a birthday, is a Stormtrooper and he looks cool. If down the line you want to go more screen accurate, then start making your mods. You will get a lot of good advice and suggestions from your fellow troopers here.