Hardware
My previous exposure to Android powered phones was the Motorola Droid. With an ARM Cortex A8 processor and 16 GB memory, it was definitely not a slouch in the hardware department when it came out. This phone had a processor and memory that challenged the capabilities of my first desktop computer in college. The Samsung Galaxy S 3 posts numbers better than twice as high as the OG Droid. Memory is expandable to 64 GB and the form factor is nearly an inch larger on the diagonal.Software
Two versions of Android later, the difference is noticeable. Also noticeable is the change from Motoblur to Samsung TouchWiz. Having never seen pure Android UI I can only make the comparison from one manufacturer's interface to another. Google has built in and standardized a great deal of functionality into the operating system while allowing manufacturers ample leeway to differentiate their product; not always for the better.I don't like most of Samsung's software on this phone.
The saving grace is that, under Android 4 and above, you the user can disable any application you want, including most of Samsung's proprietary code. In fact I've done this with many apps, killing the original calendar, music players, and S Voice, along with some other bloatware. Sorry Amazon Kindle app and Facebook; you're gone. Fortunately, as an Android phone, the Galaxy has full access to the Google Play Store, where I was easily able to replace and expand the phone's built-in software.