I now have both the TX and the 770. If you use any online media, the 770 by far out does the TX. The browser alone beats anything on the palm, and multitasking makes it a joy to use. But, the TX is great for calender and contacts. You just press the hardware button and up comes the calander. It's also smaller, lighter, and quicker for those purposes. And it has an alarm clock as waddell said.

What do you need to use these devices for?