I’m a web developer and I’ve switched to a 12.9" iPad Pro for my primary device. I say primary because anyone in my field is managing multiple servers remotely all the time, so there will never be only one single computer in my life. However, I’ve chosen the iPad to be the driver for everything I do and it’s been an enjoyable experience.
I’ve always edited code in a terminal, so Blink is a fantastic app granting me access to tmux and vim over mosh for a seamless workflow. Additionally, the SFTP app FileBrowser provides a convenient interface to browse my servers and upload files. There are wonderful image manipulation apps available such as Pixelmator and Affinity Photo/Designer, so no problems disecting PSDs from designers and preparing image assets.
Weakness are present in two main areas: image optimization and web inspectors. In both cases, I fall back to my always-on 2009 Mac Pro:
ImageOptim is an incredible macOS tool for shrinking images, so I’ve combined Dropbox and Hazel to make an “Optimize” folder available in the File app. I drop an image in there and seconds later it’s replaced with a web-ready version.
Nothing can touch Google Chrome’s web inspector on the desktop, so I’ll sometimes use Screens to visit my Mac Pro when I need to debug a website. Alternatively, I use a third party service CrossBrowserTesting which also lets me test browsers from other operating systems. There are iPad apps I use (Inspect, Web Tools) which are super helpful but not as full featured as Chrome.
I don’t mind the additional dependency, because I’d keep my Mac Pro running regardless. I still need it to host my Plex Server, as well as managing my iTunes Match library (drives me nuts I can’t add/edit songs on iOS!). But I rarely sit in front of it anymore and just visit with my iPad.