ETP you are the main account... basically, you're the top of the chain. I personally don't want subresellers because if your ETP goes poof, you might not be able to do some of the things (dunno if this is true, but I did hear about bad moving experiences because ETP went poof and subreseller couldn't do anything for my friend)...
The only thing honestly, ETP can change your pricing, see what domains you register and change you from a retail to a reseller. Other than that, nothing (that I know of). If an ETP goes belly up, no you keep your account.