https://www.cnet.com/news/ipad-pro-2018-vs-surface-pro-6-which-tablet-is-the-best-laptop-replacement-in-2019/

On the upside, if you're shopping for either the 2018 iPad Pro or Surface Pro 6, you don't have to worry too much about it being immediately replaced with a new model. While rumors are swirling on new iPads, they aren't for the Pro, which was announced last November. (We may see an updated entry-level iPad or iPad Mini more sooner than later, though.) Likewise, the Surface Pro 6 was announced last October, so it's unlikely to get a full update anytime soon. 

For many, the iPad Pro's mobile operating system makes it a complete non-starter compared to the Surface Pro running on full Windows 10 Pro. Having Windows 10 means you can run full versions of traditional Win32 software and much more that Apple's iOS simply can't.