I try to make it where I only buy from TFsource, and that's if they don't carry a certain item but that is almost never the case they always have the transformers I'm looking for. They also have great customer support and bullet proof packaging as they say.
These guys have it down pat. Good prices, extremely fast shipping, and excellent product. As a long time customer of another "Big" Toy Store online I'm only buying my TF's from TF Source.