i posted in another thread about this, but I have a full body zagg invisible shield and it actually makes the phone fit more securely in the dock. Without the shield, the phone just sits in the dock and when u try to use the touchscreen the phone falls out of the dock since there is nothing holding it in. To me, the dock is poorly designed for holding a touchscreen phone.
However with the shield, it adds a little bit of bulk to the phone. Making it a more secure fit. I can now actually use the touchscreen and not have the phone fall out of the dock.
The only drawback is that the connection sometimes goes in and out, but i'd rather have that, then having my phone falling on the floor all the time.