I've been using the phone for a while now, and thought that I would write some sort of review of it. I have now used it for long enough to form a better picture of it.
I must start by addressing the battery issue that I wrote about in the comments. When I got the phone it had really bed battery life. I had to top up the charge twice during the day to get me to the evening. There was also the Google play services that seemed to take up 60-80% of the used battery. This was probably a temporary bug in some sync service, but it has since resolved itself. The battery life has also drastically improved, yesterday I tried to re-calibrate the battery by removing the battery calibration data and running it from 100% to 0% to 100%. I however failed, despite of heavy usage, on account of the battery not draining before I had to go to sleep. I got it down to about 15%, but then had to plug it in to the charger to have a full charge the next morning. Suffice to say that I'm now very happy with the battery life, it's noticeable better than the Galaxy Nexus, and should get you through a day on one charge even if you use the phone quite heavily.
I have had some opportunities to test out the sound capabilities of the phone, and must say that I'm really impressed. As I wrote before, the headphone sound is very good. Easily the best of any phone I've ever owned. The speaker is quite ok. It's certainly not up to the quality of the HTC One, but it's lightyears ahead of the Galaxy Nexus. And it's certainly loud enough.
Then to the camera. I freaking love this camera. I might lose out to the iPhone 5 and the high end Lumias, but it's really, really good. The image quality is good in normal light and in low light, and the led flash is quite good for a led flash. It's also quite fast, especially for sequence shots. This enables some of the cooler features of the camera, namely fast HDR and a mode where you hold down the shutter and the camera snaps off lots of pictures in fast succession. You can then choose to save the best one, all of them or delete some of the shots. It also have facial recognition and auto-stitching for group portraits, a feature that I haven't gotten around to trying out that much yet. It's missing the photo sphere of the Google camera, but that was mostly a gimmick anyway.
Also I have grown quite fond of the Sense 5 interface. Beside a few graphical choices that I don't quite agree with, I think it really is better than the Google Vanilla interface. I haven't had any urges to install Nova Launcher on this phone. And Sense really have great widgets, they complement the normal android widgets very well. It hasn't even bothered me that the android version is still on 4.2.2. The changes to 4.3 was mostly things that wouldn't really show on Sense anyway. Hopefully there will be a KitKat update at some point, but it's quite possible that the One will get it, but not this handset. I'm not worried about that however, because some will make a rom for the One X+, I'm sure.
All in all I'm very pleased with the phone. It's a really solid piece of hardware, and the software is top of the line. Quality wise HTC is surely one of the best Android phone manufacturers at the moment, certainly their hardware compares favourably to Samsung and others. In my opinion it's ever better that Apple. And the One X+ is no exception to this, the frame is very solid and doesn't feel at all like plastic.