So which technology is going to win out?
None of them.
It's not really a difficult question. The pay TV providers - Comcast, DirectTV, FIOS et al are going to win. Just like they won the battle of the DVR. Only this time the battle will be even easier.
Their "killer app" is convenience. The last thing the average user wants to do is buy yet another device they have to figure out how to install and maintain and eventually upgrade. They are much happier to let someone else do all the work for them.
And it's fairly easy for all the pay TV providers, be they cable, IPTV or satellite to add access to both the internet and internet-based content providers like Netflix and Hulu. The winning solution doesn't have to be anywhere near as elegant as some of the current interfaces: it just has to be considerably less of a hassle.
That's what took TiVo from a verb to "are they still in business?" The DVR/cable box combos of the late 90s/early 00s were pretty clunky. But they were practically free, didn't take up any extra space and were installed, activated and fixed by your local cable guy.
The other killer app here is that the pay TV services own the internet pipes. Something like 90% of Uverse and FIOS customers get their internet and TV service from the same provider and the numbers for the cable services are not far behind.
That means there's not a whole lot that Apple or Google can do: unless they somehow manage to wire the entire US over the next few years (or buy one of the companies that has) they are at the mercy of whoever is bringing the high-speed broadband connection into the house.
Now for the good news: your cable TV provider owning access to all the new internet-based TV services may actually be a good thing for you.
Here's why: Broader access means bigger viewership numbers for all those internet-based content providers. And smaller numbers for the existing broadcast TV networks. Your service provider should be able to use that to push down the exorbitant fees they've been paying the broadcast networks all these years.
Which, if you're lucky, should get passed on to you in the form of a lower monthly cable bill.
Which is something no one would object to.
UPDATE (11.4.11) Today brings news that Google may be stepping up their game: they have been using Kansas City as a test market, and there are reports that they are looking to roll out a full-on Triple Play service there to compete with telcos and cable companies. If it's successful, the question remains as to how quickly they'd be able to roll something like that out nationally.