Google's Android mobile OS appears to be the first real challenge to the iPhone, providing an open platform for users and developers, along with much iPhone-like sophistication. The first device, the T-Mobile G1 from HTC, is expected to ship on Oct. 23.
Pros: Physical keyboard; PDF, Word, and Excel file viewing; cut and paste across apps; multiple simultaneous app execution; strong HTML support; open source dev platform; built-in RSS reader.
Cons: Supports only Gmail; syncs only to Google's hosted apps (no desktop syncing); limited file support; initially low number of apps; no support for iTunes libraries.
Unknown: Security capabilities.