I have a Targus Bluetooth keyboard. I dont know if its my phone, the keyboard, or the fact that it uses Bluetooth, but there is a lot of lag when typing. And mine disconnected randomly as well.
An adapter will allow use of an xbox controller (not sure if it works with galaxy tabs) as well as a mouse, usb stick storage. With the 30 pin hub, you can leave it and the accessories on the table, and just unplug the 30 pin connecter to take the tablet elsewhere. But the Bluetooth keyboard of course will offer more portability.