Phone because I don't use my laptop or tablet much anymore.

My laptop. I got things done much faster in my laptop.

Computer. I can see a lot more on the screen at a time, and typing is so much easier.
Edit: Oh yeah, and, like Kate said, switching between tabs is a pain in the ass on a phone. So is copying and pasting. And knowing where your saved image went. And bookmarking to a specific bookmarks folder. Etc.

I prefer to browse on my laptop. I have a dozen tabs open at any time and my display is superior to any phone.

For a long time it was my PC. But when it burned out. I resorted to my Phone.🙂

computer, because hunching over a 3.5 inch screen is bad times, zebra porn was meant to be displayed in glorious 4K

If I need something fast my cellphone is better.

Laptop. It has a "big" screen, and a keyboard!