Depends on what’s important to the user. UR824 has more channels, due in large to it’s extensive digital expansion and again there is a lot of DSP power under the hood. OTOH, the Scarlett definitely has better quality innards, but possibly not enough that you are going to notice in the end. But why do you think the likes of Prism Sound interfaces are held in such high esteem? Because the tech specs of their inner parts are beyond repute.
Personally for my next interface, I’m keeping my eyes on MOTU’s Ultralite MK3, which you may want to give a look Larry. It’s about $550.