I'm assuming "[NEW] Added preliminary support for 1Password.opvault files!" refers to Dropbox support, since I'm under the impression that iCloud sync already used opvault. So I switched to opvault for Dropbox syncing and wanted to let you know I haven't had any problems. To get an opvault file, I switched to iCloud sync on my Mac, copied the resulting folder from Mobile Sync to Dropbox, then renamed it to 1Password.opvault.
1PasswordAnywhere in opvault would be great. I mention it in case opvault Dropbox syncing in the iOS beta heralds opvault as the default sync format. If that's the case, I'd like to transition to opvault, but 1PasswordAnywhere is a must for me.
Side note: I'd like to request an update to 1PasswordAnywhere so that it at least uses the new item types instead of Accounts and Wallet.