Both are file managers used as an alternative to My computer
In the past i used opus for more than 8 years and also using now currently

Features lacking in opus ---

1)Option to open files by single click is not there

2)Bold font for active tab is not there

3)Icon to toggle between details mode and thumbnails is not there

4)In opus if the breadcrumb bar's navigation buttons are removed then some of the features of breadcrumb don't work like it doesn't show downward path

5)No silent update

6) File copy and move dialogue's(screen's) are not feature packed

7)No,live filtering of item's in list

8)Default keyboard shortcuts are not easy to use and natural

9)No,on the fly font size changing

10)No restore selection for e.g if you have selected some files and accidentally clicked somewhere else then the selection is lost ,this is not the case with xyplorer.

11)No option for displaying file's age(by which one can know how old a file is,like to show as 3 months or 5 months) as opposed to current time

12)Various views in one icon for e.g details,tiles,different size for thumbnails is not there

13)No in built dark theme

14)Branch view is not very good

15)No visual filter for files for e.g to see quickly files modified within a certain period like modified 3 hours back or 1 day,2 days etc...

16)Name columns width adjusting is not remembered automatically as a user changes it

17)Can't iconize a tab

Like the above point's there are still many features not available in opus.While in xyplorer all the above features are there and many other's also.