Both the BlackBerry and iPhone are annoying when it comes to handling calendar invites, but the iPhone is worse. If you get a calendar invitation as an e-mail attachment on an iPhone, you can't accept it from your e-mail; the iPhone can only sync calendars already handled by Exchange. Plus, you can't move an event from one iPhone calendar to another, such as from your personal calendar to your work one. That's just dumb. But a BlackBerry doesn't recognize multiple Exchange calendars, so even if you distinguish private from work calendars in Exchange, the BlackBerry does not. The same is true if your desktop calendar app has multiple calendars; the BlackBerry sees them all as one. (The BlackBerry treats events in each e-mail account, plus those in your synced desktop calendar, as a separate calendar.)
Another area where the BlackBerry hung me up: I could accept some invites sent to me, but not others. The BlackBerry would often tell me that I could not accept invites because I was the meeting organizer -- even though I was not. The BlackBerry also overloads you with calendar item details when you open an invite -- it's overwhelming and not necessary.
The iPhone clearly has some issues, but for such a mature platform, the BlackBerry is surprisingly mediocre when it comes to e-mail. The iPhone makes it easier to read, send, and organize e-mails and contacts, but it falls short when it comes to zipped attachments, handling invites, and searching e-mail. Both disappoint for calendar management.
RIM has made a lot of noise about its BlackBerry App World store, and Apple recently celebrated its 1 billionth App Store download. Make no mistake: The selection of BlackBerry apps is not only limited, but the apps themselves are typically pale, pathetic imitations of iPhone apps. (Compare the New York Times or Salesforce.com on the two devices, for example.) And downloading an app to the BlackBerry usually means wading through several pages and prompts. I much prefer the iPhone's simple, fast approach to downloads. Like much of the iPhone UI, the App Store recognizes that you're using a mobile device and that six-screen legal agreements and endless "Are you sure" confirmations are not mobile-friendly. If you download an iPhone app by accident, deleting it takes a couple seconds -- and the whole download-install-remove process takes less time than just starting a BlackBerry App World download.
To add insult to injury, there's no desktop version of the App World store to peruse available options, as there is for the iPhone, and the BlackBerry's tiny screen makes it hard to do any real perusing or searching. I was also put off by the fact that the BlackBerry App World functionality itself is a BlackBerry app, requiring a download before you can even get started. Not only that, but downloading App World to the BlackBerry from my desktop system via a USB connection required me to use Internet Explorer as my browser. (As a Mac user, I can't.)
The UI for managing apps on the BlackBerry is pathetic. There are at least four places that apps can reside on the device, so finding them is an unwelcome Easter egg hunt. On an iPhone, they're easily and consistently accessible, and infinitely easier to organize than on the BlackBerry.