| Stylish | userChrome.css and userContent.css | User scripts (Greasemonkey) | Opera site CSS | |
|---|---|---|---|---|
| Can modify site design | Yes | Yes | Yes | Yes |
| Can modify site content | No | No | Yes | No |
| Can modify application design | Yes | Yes | No | No |
| Malicious style or script possible | No | No | Yes | No |
| Turn on takes effect | Immediately, usually | After restart | After page reload | After page reload |
| Turn off takes effect | Immediately, usually | After restart | After page reload | After page reload |
| Applied | When page begins loading | When page begins loading | When page finishes loading | When page begins loading |
| Easy installation of styles or scripts | Yes | No | Yes | No |
| Easy to find updates to styles or scripts | Yes | No | No | No |