Jelly Bean: 41 Flavor Mix

Android 4.1 (Jelly Bean) includes the following enhancements to Android 4.0 (Ice Cream Sandwich):
- Faster performance
- Improved predictive keyboard
- Easier photo sharing
- Voice dictation (called Voice Typing) and search (ala Siri)
- Improved notification
- Google Now (uses Google data to anticipate your wishes)
- Revamped Google Play
In our opinion, the significance of the improvements are in-line with what we'd expect from a .1 release, with the exception of Google Now, which may raise some privacy concerns.
What really gets us stoked, though, is how Jelly Bean improves CPU utilization. As part of a demo, Google showcased a Galaxy Nexus running Android 4.0 next to one using 4.1. The difference was clear. The Jelly Bean-based Nexus looked a lot more responsive. What, exactly, did Google do?

According to GeekBench, we're getting a slight improvement in memory performance, but the processor score doesn't really look any better. Moving on...

A boost to graphics performance is much more quantifiable. In each GLBenchmark sub-test except for one, frame rates increase. This has two effects. One, the UI feels much smoother. Second, better GPU-oriented optimizations lessen the workload handled by the CPU, making it more available for running apps.
We really need manufacturer black list for bad upgraders!
It'll be great if we can increase UI smoothness without significant cost of battery, I'll upgrade to JB in a heart beat. But I value battery life > "smoothness".
I thought they're giving out Galaxy Nexus preinstalled with JB at Google IO, can't someone run the battery life against the "old" Galaxy Nexus on ICS.
That's a good point. Seriously, the battery life problem in mobile electronics needs some real attention here in the next couple years. Smoothness on phones and tablets doesn't need too many more improvements for quite some time, it's the battery life people!
Now I just hope I'm not left hanging for a JB update on my Nexus S, like with ICS.
Because promising an update and only delivering for 1/3 of the models, and leaving the other two hanging for another 5 months with no feedback was definitely a great experience
I installed the JB ROM on my VZW Nexus, and I'm not noticing much of a difference so far (it was pretty terrible on 4.0.4). We'll have to wait for conclusive tests to determine the real draw on battery.
Some things will inherently draw more battery - Google Now is great, but to get the maximum utility the GPS needs to be left on so it can recommend Places literally right next to you.
The experience overall is significantly smoother than ICS was, so I'm looking forward to the actual release and the tweaks in the incremental updates.
In regards to the Nexus 7 - this is an amazing tablet. It does more than the Fire does, and the only thing it can't do is Amazon Instant Streaming (which in reality is basically Netflix's library). I owned a Fire and though it was a huge letdown from day 1; ended up with the Nook Tablet and felt the device and OS were much better crafted, just lacking in content.
Google needs a way to force every manufacturer to make their phones at least 4.0... Tired of LG king n update every century.
IPad spellcheck is very finicky.