Works amazingly, just purchased mine this week and used it for the first time last night. Kinda nice to have a 7in GPS unit to view. Charges while you drive and it has rubberized tips to very firmly hold the Tab in place. Worth every penny!!!
The only issue I can find is that the Samsung designed Car Home App does not work with the Tab as stated in the dock's manual. Works on every other Samsung Galaxy device but you can't find it in the market for the Tab. It's super useful when driving just can't use it on the Tab. There is an free Car App that works on the tab if you search in the Market. Try it out, it's called Car Dock Home v3.