I think the agile communications stuff looks really nice and is certainly down the road. It's also pretty clear that SIP is certainly the future, whether that time is here yet or not is another story.
Almost every vendor has implemented SIP including the the video conference bridge vendors (Polycom, Cisco, etc). The issue right now is that everyone's SIP standard is different and they usually don't interoperate well. That's where you have Cisco's Session Manager and Avaya's Session Manager which promise to provide an adaptation layer to help make the different SIP devices interoperate.
Avaya Aura is actually quite a few different solutions. We're currently getting ready to replace our Octel 350 with Avaya Aura Messaging in conjunction with Aura Session Manager and Aura System Manager (managing a collection of CS1000s). Ask me in a few months what I think about Aura.
Cheers!
