As of version 1.8.10[1], which includes my merge request[2] to add an '--output' option, it has even completely replaced my use of 'dd' for writing disk images: 'sudo pv -Yo /dev/mmcblk0 whatever.img' is nicer, has much better progress indication, automatically selects a more sensible buffer size, and begets fewer groans from UNIX neckbeards, than the old 'sudo dd of=/dev/mmcblk0 if=whatever.img'. (The '-Y' causes pv to sync after each write, which greatly improves progress indication in Linux.)
Though it's useful for much more of course. I use it for progress when compressing files ('pv blah | gzip ...'), when uploading files to the web ('pv blah | curl --upload-file - ...' — curl doesn't show progress when uploading for whatever reason), or just when I wanna see that something is happening with an operation which would otherwise take a while (even things like a slow 'du -h /some/path | sort -h' benefits from a 'pv' squeezed in the middle just to indicate that something is happening).