I don't know about drop-in Ubuntu replacements because I don't think I've ever installed Ubuntu without regretting it.  But I've been using MX Linux for several years now, and it works very well.  It's pretty much straight Debian, but with multimedia and some other stuff.  I install the XFCE version, then install TDE.  Install is pretty painless, especially if you keep your home directory, which is a lot easier if you use a separate /home partition.  The one thing I don't like is usually having to reinstall when it changes to a new Debian version, but I haven't yet found a rolling release that can use TDE.