However I do wonder if Bethesda will patch up from the beta. Or that they'll re-release the DLC. If its the second then potentially after the beta my beta-played saves might not be compatible with actual release of Dawnguard. Meaning that I have to reload an older save and do it all again.
If this is the case then I'd rather not do the beta. I plan on using these characters in future DLC as well. I'm okay with having to replay because of a game breaking bug but if it is known that I have to replay even if I don't encounter a single bug then I won't join the beta. Does anyone something about how Bethesda plans to do this?

only US 
hup Holland hup 

To test their awesome product.