We ran a Ch6-300 for 5 years at a DZ in Cape Town, South Africa. The reason we bought it was that we could not afford a C206.
At sea level it served us well as a reliable work horse for students, training progression - including linked/floater exits and demo dives.
However we found that it is not the ideal jump aircraft for the following reasons:
Low cabin roof
Floor is not flat
Small(ish) door
The above slowed down exits for 6 way formations
Throttled back it loses altitude fast with floaters
If you can afford it go for a C205 or C206 with either the front door or rear cargo doors.
It is far better suited to skydiving operations.