I have used both Sketch and Photoshop for web design. Sketch, by far, has some key items that are immense timesavers. Check out more details at Sketch vs Photoshop.
It looks like it might be time to switch to Sketch for web and app design. This article compares Sketch and Photoshop and every time, Sketch sounded like the better option. That isn’t to say that Photoshop isn’t need for other applications… just to say that Sketch seems more when it comes to designing websites and apps.