I've have a switch but steam deck is one of the best purchases I have ever made. It's such a beautiful device. Not to mention you can change the internal storage and add expandable storage. The biggest advantage steam deck has is its community.
Storage expansion is great. I got a 2tb SSD form AliExpress for ~160CAD and put in a 1tb SD card. I can just install whatever I want and never worry about shaders or games using to much space.