Performance
Quad-core processors are the latest craze in smartphones and HTC One X is the first smartphone to launch with NVIDIA Tegra 3 processor. Thanks to the quad core processor and 1GB RAM on-board, the performance is simply exceptional and there is no lag or sluggishness. Company has included an 1800mAh battery on the smartphone, which results in about a day backup on moderate use. It is not user-removable, which is a slight dampener.
Samsung has also gone for 1GB RAM and a quad-core processor in Galaxy S III; however it is company's own processor - Exynos 4 Quad. Similar to Exynos 4 dual in Galaxy S II, Exynos 4 quad simply blows the competition away, which also includes HTC One X. Thanks to the superfast processor on-board, Galaxy S III glides through the menus, homescreen, heavy webpages and more without showing any sign of strain. Samsung has opted for 2100 mAh user-removable battery, which would easily last a day on moderate usage. The user-removable battery on S III is another advantage that this Samsung flagship holds over One X.
Software/ UI
Pre-loaded with Android 4.0.3, HTC's One X comes with all new version of company's Sense UI. A refreshing upgrade from earlier versions of the user-interface, Sense 4 is toned down, which is a welcome improvement but a lot still needs to be done. Sense 4 is still a big memory hog and takes up big chunk of RAM, but thanks to the 1GB RAM on-board the performance isn't impacted that much in the real-life.
Similar to HTC, Samsung has also included its own user interface atop Ice Cream Sandwich, called TouchWiz Nature UX. Company has also included several other software features that are S III exclusive right now. Some of them are Direct Call, Smart Stay or S-Voice. While Direct Call and S-Voice work well, Smart Stay is somewhat hit and miss. There are other disappointments as well like the tweaked folder functionality. One other thing that also needs to be kept in mind is Samsung's poor track record with Android updates.