My experience has been a little more on the negative side.
I don't use the bank for anything fancy, simple day-to-day banking. My private banker got replaced 3 times this year and the current one does not seem interested in taking my calls. (Investec replaced them, not my request) I have to phone the backup banker to get anything done most of the time. When I moved over 2 years ago they were very helpful, right until I was a client.
Basic things like buying prepaid electricity are painful. The app either times out and you have to do the same transaction twice or it times out and a minute later you get an SMS token. Capitec is instant.
Instant payments sometimes take hours to reflect. Again, Capitec is almost instant.
For investing and forex I guess they work well, but day-to-day banking is terrible. Not worth the almost R 600 monthly fee. I'm busy moving back to one of the big 4 where the basic functions work well.