FTTH Active vs Passive

I'm wondering what everyones thoughts are in regards to FTTH using Active Ethernet or Passive. I work for a FTTH Provider that has done Active Ethernet on a few networks so I'm always biased in discussions, but I don't know anyone with experience in PON. I've read before that almost all PON technology is proprietary, locking you into a specific hardware vendor. However I think this is changing or has already changed, opening PON up for interoperability. Can anyone confirm this? Thanks in advance. :Luke Marrott