I spent some time with it at Best Buy, on two different occasions over the past three days. It's definitely a feature that has lots of potential, and makes more efficient use of the keyboard space on the laptop. The 'F' keys, with their static function assignments (and confusing mix of alternate functions on them) was a real place for improvement, and Apple came up with a great idea.
For example, when using Safari, the center of the Touch Bar becomes a soft key to enter a URL or search term. Then, after you've opened several web pages, that same section becomes a short cut way to jump between tabs, with small images of the current open tabs.
It takes a little bit of time to re-train yourself from using the mouse (or touchpad) to click on something on the screen, but once you get used to doing the same operation on the Touch Bar, it becomes very intuitive and logical to have the functions there.
One of the biggest features that I like about it is the TouchID switch to read your fingerprint, and enable the use of Apple Pay for online shopping. No longer a need to use two devices to shop online with Apple Pay.
There is also a Siri button on the Touch Bar, and Siri works very well on the new MacBook Pro. You can use your voice to open applications, perform searches, change the volume of the sound, etc. If it works that well in a loud Best Buy store, imagine how well it works in a quieter home or office setting!