One of games my family loves to play on the iPhone is Trace and like many games, you need a very sensitive and steady touch to play it well. As gaming becomes a more important function on mobile devices it is crucial manufacturers competing in the consumer smartphone market take this into account.
This is why it came as a surprise to me that the Motorola Droid has a much less accurate screen than the iPhone according to MOTO labs (no relation to Motorola). As you can see from this post, lines on an iPhone are generally straight while on the Droid they zigzag.
The HTC Google Nexus One however does a better job in this regard and the HTC Droid Eris is fairly accurate as well.
One limiting factor of the iPhone which the test showed is there is a lack of sensitivity at the edges of the screen. This is something Trace users can attest to as well.
The takeaway from this post is the mobile phone has become a true Swiss Army knife of life and you need to take into account myriad applications when you roll them out. Battery life, GPS, gaming, texting, surfing, oh and of course perhaps less but still important - talking.