Fast Learner
First Post
You're conflating "UI system" with "app launching system".Well.....that's kind of a loaded complaint. The performance paradigm has been set by Apple obviously. But one of the ways they do that is by making their UI *simple*. I'm not sure it's even a UI. IMO, descriptions of it being no more than a grid of icons do seem correct to me.
The iOS UI framework -- not Springboard, its app launcher -- is called Cocoa Touch, and it handles all of the drawing, scrolling, keyboard stuff, gesture recognition, etc. (it handles the non-visible stuff, too) of every app. The same is true of the Android OS UI system and HP's WebOS UI system.
An easy example of the kind of sluggishness/sloppiness you see in reviews is a simple drag test. Pick an app that has something that can be scrolled across the screen, like a web page or a list of items. Place your finger on the draggable thing near the bottom of the screen and drag your finger to the top, stopping before you leave the screen area. On iOS whatever you placed your finger on when you started dragging will still be precisely under your finger up at the top, but on other tablets your finger will have "slipped" ahead of the content.
Similarly if you tap on a buttons in the various OSes, whatever UI thing the button does to acknowledge your touch -- light up, animate to appear to press into the screen, whatever -- will happen instantaneously on iOS but often has a delay on other OSes. Now mind you, the delay is usually measured in tenths of a second, but it's just enough that it doesn't quite feel like you're touching a physical button.
I'm not fanboy-claiming that iOS is the end-all and be-all, I'm just explaining how things can feel sluggish in a touch OS regardless of the processors and such. Apple was able to polish and refine that whole interface for years before releasing the first iPhone and even more years before releasing the iPad. I'm sure that Android will come up to that same level given sufficient time, but in the meantime app use simply doesn't feel as snappy on competing tablets.
Of note, Windows Phone 7 is probably the closest to iOS in terms of feeling snappy, but that's no surprise in that Microsoft has also had a bunch of years to work on it.