[Android Q&A, Help & Troubleshooting] cb474:
I wouldn't totally write off the Nexus 4 yet. I'm still considering it. Partly because it is a very good deal, for an unlocked phone. The One X+ or Xperia T and Optimus G will probably cost almost twice as much, unlocked.

And I think devgee is correct that the review units for the Nexus 4 did not have the final consumer version of the software on them yet. This might address the battery life and cpu benchmark issues. (It's unfortunate the reviews get published on devices that aren't really what will ship, because any improvements or changes can get overlooked later. I don't know if these reviewers will go back and retest the device.)

For me, it's the minimal storage on the Nexus 4 that makes me hesitate the most, but maybe I can learn to live with it.

If you like the Optimus G, it's definitely worth considering, since it doesn't have the storage limitations of the Nexus 4, and it tested well for battery life and in the cpu benchmarks. And some versions have a higher resolution 13MP camera. But you give up the pure Android experience. And as James.UBC points out, I don't know that it will have as many custom ROM options as the One X+. I don't really like the design of the Optimus G, but that is entirely a superficial reason not to get it and only my personal taste. Some people think it looks great.

I agree that it would be nice to have the S4 Pro chipset. You can also get this in the Asus Padfone 2, which is a cool phone. It also has 2GB of RAM, the Adreno 320, LTE (for certain frequencies), a 2140 mAh battery, and 16/32/64GB storage options. Plus there's the tablet attachement, if you're into that. Its big downside is that it may have no custom ROMs for it at all, if you want that. I think the original Padfone had basically no development. It's a bit puzzling, because this is a cool phone.

I also agree with James.UBC that the One X+ has a great design. To me its main downsides are that it will be much more expensive than the Nexus 4, unlocked (probably $600US or more). And I don't know if it will have an unlocked bootloader, depending on which version I want to get. And even if it does, I'll have to wait for the development community to catch up and release a ROM that will give me a stock-like Android experience (I don't like Sense). And of course, it has a very good CPU, but one from the previous generation of architecture. I tend to keep my phones for a while, so something that is as future proof as possible is good for me.

Anyway, I recommend that you read reviews of the devices you're interested in on the sites I mentioned in my first post and search around for other reviews. Reviews are easy to find and you get a sense pretty quickly of how thoughtful and knowledgeable the reviewer is. Then keep an eye out in the reviews for comments about the features that matter to you and any problems mentioned. I wouldn't take any one particular review as necessarily right. But if you read several, you start to get a feel for what the issues are.

In the end, you probably can't go wrong with any of these devices either. It really comes down to a matter of personal taste and which features are most important to you. No one device is the best one for everybody.