1. No 3G Data...Yet
The PlayBook, when it first ships, will not have a cellular radio at all. It will have Wi-Fi and Bluetooth, but won't be able to access wide-area networks. The iPad has a built-in 3G cellular data modem. RIM said a 3G version of the PlayBook is coming, but it won't street until the second half of 2011.
2. App Support
Even though RIM pitched developers with a completely new set of tools for its operating system(s), the PlayBook will start off with very few native applications. The iPad was able to tap into Apple's iPhone App Store from day one, and already has more than 25,000 apps designed specifically for it. The iPad also has access to Apple's iTunes ecosystem for content.
3. Unproven OS
What's QNX software? When Apple launched the iPad, it did the smart thing and used the same operating system used by the iPhone and iPod Touch - a.k.a, known and proven successes. No one knows anything about this new QNX-made operating system and how consumers and businesses will react to it.
4. No GPS
According to RIM's spec sheet for the PlayBook, it has no GPS. The 3G version of the iPad does have GPS. Without GPS and without cellular data, the PlayBook won't be the best tool for navigation and directions. RIM hasn't said if GPS will be included in the 3G/4G versions of the PlayBook.
5. Limited to 32GB
The top-end PlayBook has 32GB of on-board storage for media and content. The top-end iPad reaches twice that, up to 64GB. While 32GB will probably be enough for most people, that extra storage on the iPad means twice the movies and twice the music.