iPad all the way for me, but...
Yes touchpad is cheap and may meet your needs, but as hp has dumped it and the OS, I don't see much in the way of apps/3rd party support. You judge based on what you want from the device.
If you use blackberry phone then the playbook?
Of all the android devices the ASUS transformer is the most interesting and generally receives very good reviews. If I was going non iOS, then this is where my money would be.