I own an Acer Iconia Tab A200 for a few weeks now. Compared to the iPad 1, that I had before, I see the following advantages/disadvantages:

• The A200 has a higher display resolution and it’s therefore a bit sharper (the new iPad 3 should be even better), which makes it more comfortable to read eBooks.
• There is an USB-port on the A200, so you can attach an USB-drive or a mouse or keyboard. Furthermore you can insert a Micro SD Card directly.
• At the moment there are more optimized (and useful) apps for the iPad compared to Android tablets. Especially when it comes to eMagazines.
• The support for google services on Android devices is generally a bit better compared to iOS. That’s only an advantage, if you, like me, use them a lot.
• Official support for Apple services on Android devices doesn’t exist.
• The iPad (even it was the first generation) was a bit more stable and smoother.
• The battery life of the iPad was better also.
• Adobe Flash is supported on the A200, while not on the iPad. But Adobe announced, that Android 4.0 will be the last version, that will be supported.

These are just my personal impressions. Others might not agree 🙂