Hi moosetracker! I imagine SA Scouts are a bit unknown, American Scouting is definately more familiar - even here our kids see it in movies, the internet, etc. quite frequently. From what I understand, the SA scouting system is still very old-school and runs very similar to the original English system and age groups that BP uses. We do modern skills training, but haven't added things like Venturers to our system. For us it runs something like this:
Cubs (ages 7-11): They have an 5-step 'advancement' program they work through, with Leaping Wolf being their final award.
Scouts (ages 11-18): Also a 5-step program starting with Pathfinder -> Adventurer -> First Class -> Explorer -> Springbok. The Springbok is basically the South African 'Eagle Scout' and is the top award a Scout can achive in South Africa.
Rovers (ages 18-30): Also a 5-step advancement, ending with the top B-P Award. I think many associations have removed the 'Rover Crew' and formed sections like the Venturers, but this is not the case in South Africa. Rovers aren't really regarded as youth members, we are adult members - but the difference between Rovers and Scouters is that Rovers focus on personal development and service - think of it as scouting for young adults where we focus on things like the writing CV's, starting businesses, running big scout and community service events, etc. Many Rovers (myself included) are also Scouters, but for a lot of young adults the commitment of being a Scouter and making themselves available every week to the troop isn't always possible. 26 is actually older than the average Rover (even though the age allows up to 30, most are in the 18-22 range), and for this reason I play a bit more of a leadership role. There is no obligation for a 18 year old leaving Scouts to become a Rover and many prefer to become a Scouter directly.
So to sum up, Rover and Scouters are basically just 2 different paths young adults can take after their 18th birthday.