Yeah, but it isn't noticeably "less stable" if at all anymore* unless you mean stable as in "essentially in maintenance mode", and clearly good enough for SLES to make it the default. Stop spreading outdated FUD and make backups regularly if you care about your documents (ext4 won't save you from disk failure either which is probably the more likely scenario).
* not talking about the RAID 5/6 modes, but those are explicitly marked unstable