The product is excellent to use. The build quality is also excellent. I will say this for Apple, if I give their build quality a 10 for their iMac, the Surface studio also gets a 10. My Apple pencil gets a 10, the Microsoft pen gets a 9. The microsoft keyboard also gets a 10. The surface dial also gets a 10. The dial is phenomenal. No lag, very intuitive. Photoshop was not installed on the machine I tested briefly, but some other photo program was and I can say editing photos will now be easy beyond easy. One of the best features of the Dial, is that you can just pick it up and place it anywhere on the screen depending on where you need it.
I wish the Studio had a thunderbolt connection, but that is because I already use a thunderbolt, external raid for my Macs. I will need to switch to a USB 3.0 external raid. As others have pointed out, the Studio does not have absolute state-of-the art connectivity. But file transfers and backups are such a very small part of how I interact with my hardware, I don't really care if that stuff takes a few more seconds on USB versus Thunderbolt.
How I interact with the hardware is extremely important to me. And on this level, my iMac is a 7, and the Surface Studio is easily a 10 for sure.
Hope this helps.