I had a manus , 3 of them , there nothing but trouble to set up , ie: Cranks/BB/ chainline , then took ages to sort my disc brake set up out , the disc mount is total gash month old frame had a crack in the middle of a weld!. Not right sure on other rockmans what there like to set up and so what. 
 
The manus rode okay i guess i changed a number of bar/stem setups and couldnt find one i liked. 
 
The koxx is so easier to set up no hassel at all! , rides much nicer to imo. The short wheelbase and high bottom bracket rise makes it feel nice to ride with! especially on natural. 
 
The weight on both bikes is very similar , but the koxx was abit lighter than my rockman manus.   
 
 
I did like my rockman at first but since i had many problems with them i wouldnt go back to a rockman.