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.
Retrospring uses Markdown for formatting
*italic text*
for italic text
**bold text**
for bold text
[link](https://example.com)
for link