I have the Samsung keyboard dock and no longer use it. After trying to get along with it for 4-5 months I found it more frustrating than it is worth. This is due to a couple of serious problems, and overall poor design.
Problem #1: Duplicate characters. The unit frequently recognizes a keypress as 2 or 3 requests for a character instead of one. As a result I constantly need to backspace and delete the extra characters.
Problem #2: If you start your G-tab 10.1 with the dock connected, every 3rd or 4th time you turn it on it starts up the Galaxy Tab in an odd "time display" mode. I found this problem documented by other users, but have not seen a solution for it. Instead of blanking the display when it goes to sleep, the g-tab switches to displaying the current time in a large format. Buttons like Home, Back, and Options work differently in this mode. While you can get things to work, it is frustrating to use. Removing the g-tab from the dock and restarting it returns it to normal. So you will probably find that you always want to turn on the g-tab outside of the dock, and then plug it in.
Design Problem #1: special function and number keys. If you are a touch typist, you will probably grow to hate the locations of some of the special key functions such as Home, Back, and Switch Sessions. When I am typing email I often forget that some of these keys are where I expect the number keys to be.
Try hitting the "home" key by accident 2-3 times while trying to dash off an email, and you'll see what I mean. Likewise the Back key - which instantly exits the email session in the Gmail app - is easy to mistake for a number key and blows away everything I have typed.
Design Problem #2: The plastic supports on the keyboard dock stick up from the dock at a slight angle. They do not fold and cannot be removed, so it is difficult to throw it into a backpack or bag to bring along. You have to pad those supports carefully or they will either become damaged, or damage something else you've brought.
My wife bought the Logitech bluetooth keyboard for the G-tab and it is much better. I borrow hers when I need a real keyboard. It has a few key placement issues as well, but the layout is much improved over Samsung's. It lays flat and snaps over the g-tab to protect its screen. It does not throw extra characters for each keypress either. About the only drawback is that you need to remember to keep it charged. It is easy to leave turned on.
Hope yours works better than mine.