More complete? There are plenty of things in iOS that ICS doesn't have and vice versa. I wouldn't say that any is more complete. I've already pointed out some features like better notifications, safari reader and others like airplay, AirPrint, better music syncing (opinion - I do not like drag and drop, I'd rather have it done automatically) and support for full local backups and of course a much better app selection. I'm sure there's more as well.
Usability is also debatable. I think your meaning of "robust" is better customisation and freedom to install and modify just about anything you want.
Notifications IMO are not better due to the fact that they lack in the most important category...notifying me! As I stated earlier, the fact that I don't get a reminder icon that tells me to take a look at the notifications is a huge flaw. Basically if I choose not to address a notification at the time it comes in, then there's a chance I may forget about it since there's nothing to remind me to look.
Safari reader, this is another one we've both been over. Reader does it in a different way (as far as formatting) than the android browser which saves the page complete with formatting. However, in the end they accomplish the same thing, they just go about it two different ways.
Airplay, is basically a similar concept as dlna except that it doesn't work on much. DLNA is a much more prevalent technology and works with many late model televisions. It also works with Playstation 3, Xbox 360, and computers. DLNA is much better to have for the simple fact that you can actually use it with a lot more products (it's more compatible).
Airprint's equivalent would be cloud print. The difference is that airprint requires you to be on the same wifi network as a particular printer, whereas cloud print can print to a printer without you being on that printer's network (it's done through the cloud). Both solutions have their pluses and minuses. Of course if one just really wants to use airprint, they can always just install it on their phone. Note: You can also use cloud print in iOS. Long story short they are at par in this category because both platforms have the same options available.
Music syncing.....well I don't particularly care for tethered syncing. I find it to be very inconvenient. However, my phone's music stays synced with my computer through the cloud. I never have to connect my phone to the computer to do this. Google music automatically uploads any new music I add to the designated folder to the cloud, which in turn is immediately available to my phone. In other words, when I'm on my computer I just simply download a song from the web, and it's automatically available on my phone without me having to do anything. NOW THAT'S how syncing should be. No wires, no having to actually go and do the syncing, it's all done automatically without me having to do anything.
Basically the things you mentioned as being an advantage, some of them aren't even really an advantage and are done in a more complete, deeper, and more thorough way. This is just an example of what I meant when I said more robust. Then there are a few of the things that I said earlier in this thread also. Does this help to clarify things a little bit more now?
