One of the biggest difference between the basic iPad and iPad Pro is the display.
The iPad Pro models have Apple's ProMotion technology, which is basically a 120Hz refresh rate that makes everything generally look smoother, from scrolling webpages to watching videos. When you're using the Apple Pencil, it also makes it feel like you're really writing on paper, thanks to that enhanced refresh rate.
That said, the new 9.7-inch iPad still has the same Apple Pencil support, and everything — from watching videos to browsing the web — looks great on that Retina display, too. You might notice a difference if you're holding the two different iPads side by side, but you're not missing much if your iPad doesn't have ProMotion.