I have both of these keyboards.
PRO:
Pocketop is minute and easy to pack, wonderful key combos to open apps, can find at extreme sale price, if you can find at all.
Targus has a real keyboard layout/feel w/separate number keys, jog dial that works.
CON:
Pockettop is minute, some extreme, non-intuitive key combinations needed for punctuation. If you are using the Z w/AC connection the connector causes Z to lean. ( I found that \"sticky-tack\" worked well to stabilize everything.
Targus is larger than Pocketop, but still transportable. Higher price.
I have chosen the Targus over the Pocketop. For several reasons, the keyboard layout, the more secure way of holding the Z, and it seems to be a little easier/faster to setup.
I have not tried the Targus in landscape, and I don\'t know how that would really be done, unless you can rotate the screen 270, because of the IR port being on a swing arm that can not be positioned to point at the port in the \"normal\" left-hand 90 turn.
I own a 5500, but assume that these will all be similar issues with the 5600.