Other companies seem to have gotten pretty lazy with their updates lately, but Asus is once again the first to update their devices to the latest version of Android. Their most successful tablet to date, the Transformer Pad TF300 (which came out at $400 at the time) will receive Android 4.2 now, while the other tablets such as the Transformer Pad Infinity, Asus MeMO Pad Smart 10", and Asus MeMO Pad will receive Android 4.2 in Q2.
As I mentioned, the others seem to have been pretty slow with the Jelly Bean updates lately, even though the Jelly Bean updates (both of them) weren't major code changes over ICS. But it still took most of them 6 months or so to even update their flagship devices (let alone the other devices in their line-up) to Android 4.1, and it looks like it's going to take them about the same time to update to Android 4.2.
If they are going to release the 4.2 update sometime very close to the Android 5.0 launch, or worse - after that - then I'd rather they just skip the Android 4.2 update and work on the Android 5.0 update, which I'm sure will be a much bigger update than 4.2 was. I'd rather wait a few more months for a much bigger update for my old device than get the 4.2 update now as the final update. Unfortunately, I think most of the 2011 devices, and even some of the 2012 ones, will stop getting upgraded after the 4.2 version.
So far Google's PDK (Platform Development Kit) doesn't seem to have done much to shave off time from getting the upgrades, but perhaps the manufacturers are using the PDK as a way to get lazier with updates, instead of delivering them 3 months earlier compared to before. That certainly seems to be the case with manufacturers who customize Android. Instead of shipping the update 3 months earlier, they now use those extra 3 months they get to customize Android even further, and ship the update about 6 months after the version's release, or even later.
This is why we, the market, should vote with our wallets, and buy Nexus devices instead, which get updates much earlier (usually in the same time with the new version's release or within weeks after that), and for a lot longer time usually, to show them that we care about how well the companies support their devices.