What makes a touch screen phone good?

Touch screen devices have been around since the Palm Pilot and the technology has since transitioned into mainstream tech. In the past, you needed to have a Windows Mobile device to use a touch screen and this prompted several repercussions — you needed to sacrifice usability with such a small virtual keypad for SMS and the Graffiti / handwriting recognition software was a bitch to use in comparison to today’s methods. Of course, the iPhone changed a lot of things and more and more manufacturers are getting into the craze really, because of that. Funny thing is, a lot of these phone manufacturers are trying to emulate the iPhone UI. So it really makes me wonder — what makes a touch screen phone GOOD?