It looks like Adfonic is rolling out carrier / connection reporting:

I think this platform has some of the best reporting, with a really comprehensive device database (I think they use DeviceAtlas from .mobi). And with this new addition might be the only one with device and carrier reporting. (maybe?)
As much as I like the 3rd party tracking solutions that have popped up, I think for someone just getting into mobile a platform like this makes it really easy to get started and still track and optimize effectively.
Also, using the data provided by the network is usually more accurate than a 3rd party tracker, as they use different databases and define devices & carriers differently.
What do you guys think about posting back to your traffic networks and using their reporting?
We support it thats why we built Network Postback feature in our tracker.
To your point about using a tracker vs just the network, with mobile there are so many networks when you start working with over a dozen vendors you're going to want a centralized place where you can monitor, manage, and optimize from.