IMO there shouldn't be a difference in terms of product within the ampule. If it's sustanon from Organon it'll be the same gear if it's from Russia, Greece, Pakistan or wherever. The ampule itself may be different i.e. used with laser inscription or on printed ink. I unfortunately can not answer as to why the Greece sust is always sold out. I'm guessing it may be because they have low shipments, but whatever the reason all Organon sust( that are legit, not fakes) have the same amount of gear inside. Hope this helps.