The HTC Flyer and iPad2 are two very different devices.  The Flyer uses the Android operating system while the iPad2 uses the iOS environment.  The iPad2 has a larger screen at 9.7 inches but it also is less portable than the HTC Flyer which has a 7 inch screen.  The Flyer also has the Scribe software for stylus-based input as well as HTC Sense.  In the end it really depends on if you prefer to be part of Apple's ecosystem or if you like Android and want a portable device like the Flyer.