The iPhone doesn't come with a document editor, but the $20 Quickoffice (left) allows for basic editing on the iPhone. Many BlackBerrys come with a free version of the $70 Documents to Go for BlackBerry (right). Quickoffice preserves existing tracked changes (unlike Documents to Go) and offers stronger Excel editing features. But Apple's SDK restrictions on the iPhone mean that Quickoffice can't work with e-mail attachments, nor can it work with Zipped files; Documents to Go has neither restriction. Neither device can be used for more than light work. Generally, BlackBerry apps are pricier and either less capable or harder to use.