Mume.net had the following advantages IMO:
1) It was simple, mostly there was just the logs and the wall to read and that's it. No YASNF.
2) No account system. ER has some obvious problems with character separation (logs from anonymous characters visible on the profile page etc) but also if you play Sherlock a little you can connect a character to a player.
3) Commenting policy. There are still some racist etc comments left on old logs which is NOT ok, but on the other hand no one ever got booted for, for example, making a funny non-english comment.
4) Like fine wine, women and previous versions of mume, logs only get better with age. And there's an abundance on mume.net.
Why did people come back to mume.net? What are you expecting from it? What did ER do that mume.net should not do?