[AT&T, Rogers HTC One X, Telstra One XL] NerdyLlama:
I don't think it's going to be 4.7" big. That's quite a shoe to fill. PPI is less of an issue for both the phones. Unless you have amazing vision or whip out a magnifying glass, you can't even see individual pixels. A higher PPI is usually a better thing, but beyond a certain point, it becomes indistinguishable.

At least with an HTC One X you can control how the multitasking behaves. However, I do want to address two issues: 1) the clearing of the text boxes has more to do with the apps you're using than the multitasking itself and 2) unlike the HTC One X, apps like Dropbox can't just linger in the background and upload new images as they're taken. I ran into that limitation quite a bit back when I still had my iPhone.

I know this may sound like blasphemy in this community, but I wouldn't ever recommend buying a phone simply based on what you can do after you root/jailbreak. Usually you can reasonably expect a method for root/jailbreak to come alone, but you can never guarantee it. Always pick a device based on how it suits your needs and desires without any extensive modifications.

All of this being said, even with multitasking being as it is on the HTC One X, I'd still recommend it over an iPhone. As previous users have mentioned, the effect of the stock multitasking setting is only visible on things like web browsers and some games. If you go under the system settings and modify its behavior, you'll probably achieve the desired effect. If you don't feel like tweaking system settings, you can always install an app like SMS Popup which lets you quick-rely to messages without ever leaving your current task.

One thing I do pride Android on is the ability to have background tasks for applications. With my iPhone I would find that (aside from default apps like Mail and Messages) certain apps wouldn't provide notifications when they should have. For example: if I hadn't launched Words with Friends since a reboot, I'd never get notifications from it. Same thing with uploading images from Dropbox.

The other thing that persuaded me to switch to an Android device was the ability to customize and personalize out of the box. On an iPhone, the most you can do is change backgrounds/sounds/icon arrangement. On an Android device you have full control over your home screen. You can manipulate icons arbitrarily (putting gaps between them, skipping pages, remove icons without uninstalling the app, etc), you can install widgets to quickly access information/settings/apps at a glance, live wallpapers, and even make shortcuts (such as a one-click "Directions to get Home" and "Sound Settings"). Heck, you can even install custom keyboards.

All-in-all it took me about a week to get used to how Android does things, but whenever I play with my old iPhone (my girlfriend uses it now), things just don't feel quite right. The best way to describe it is that on my HTC One X, I get to make the rules. I get to decide how things look and feel and how the system responds to my actions. Playing with my iPhone I feel like I'm not making any of my own rules. Sure, I can change some settings, but compared to Android it feels like a thin veil over how Apple things I should use my device.