The 10Plus is bigger in size, while the Xperia10 fits comfortably on the screen of the 10 Plus. Both are slim, a nice change for smaller hands that struggle with wider phones.
The slimness of the Xperia 10 makes it easy to fit into a pocket, something smartphones are not doing much of these days but it can also easily slip out of the hand because it is so slim.
The 10 Plus is longer, making it a little uncomfortable on the hand. The extra length is great for browsing the internet because you get to see much more content and don’t have to scroll as much as you would on a regular-sized phone.
The 6.5 inch (6 inch for the Xperia 10) 21:9 wide display is the key selling point for the phones.