I didn't try the Windows version of DOpus, but my personal opinion is that isn't so necessary unless you're doing very "hard file management": I'm used to use DOpus on the Amiga, but under Windows XP I'm pretty happy with its cut/paste/preview capabilities.
I was worried when I approached Win world not to find a proper DOpus substitute, but I didn't need it.
Well I'm not using Explorer with its uncomfortable tree-styled window, but just cut & paste with two open windows, and this is more than comfortable for moving pictures/video/other stuff around the hard disk.
Anyway for renaming lots of files I use other tools, and for viewing images I use the good freeware program Irfanview.
Going a bit off-topic, I think the reason we use DOpus on the Amiga is because Workbench, in its basic implementation (without special add-ons), is far for being comfortable about copying, renaming, getting info.
In a future release of the Amiga OS (hopefully for 68k - read AfA-AROS) I would really love to have an improved Workbench with preview capabilites (eg. through datatypes), functional tools for renaming, copying and so on.
...something like a small thumbnail in the window, like WinXP, but without the useless option placed on top (eg. publish on the Web, delete, etc.); maybe even using an external preview window, something like a minimal Multiview AppIcon... just an idea...
Pretty much following the Scalos way, or even DOpus Magellan (I bought it but at that time, I didn't like it that much - not very reactive even on my A4000 040/25 with Picasso IV).
Of course I understand some of the features would require some more processing power (eg. for previewing), but times are different from the past.