I use Worker regularly and it's always one of the first apps I install on a Linux distro. It's been developed for quite a while and it is very much a DOpus4 "clone", which is no bad thing.
It's not KDE or GTK based, but it doesn't suffer too much for all that. Gentoo is also quite good, but actually being GTK+ is a disadvantage these days because it's stuck at GTK+ rather than GTK2. For KDE users, Krusader may be worth a look.
However, I find Worker to be more stable than both Gentoo or Krusader, both of which exhibit strange behaviour now and again.