It depends on you and your uses. We like the extra grip for a few reasons:
When you carry your Surface Book or pull it out of a bag, the extra grip surprisingly adds a lot of security to prevent slips and falls of the device (particularly if maybe you had some sweaty hands).
If you're working on slanted surfaces or surfaces that tend to get bumped, the extra grip helps to prevent your device from sliding as easily.
The extra grip is a little bulkier, allowing for better airflow under your device for cooling (although, for Surface Books the bulk of the heating is in the tablet portion).
One potential downside is for users that lean their screen as far as possible, the bulkier feet change the balancing point and can make the device rock a little, particularly if your touching or using the stylus on the tablet.
On the other hand, the original is a great choice if you've never noticed that your Surface Book may slip out from between your fingers, or slide on a surface. It maintains the form and looks of your device closer to the original new state.