Voted for app.
I prefer to do setup on IB on pc/laptop and enjoy the convenience of the app for transactactions.
My eyesight is rather poor due to diabetes and I've had a couple of instances where I actually paid money to the wrong beneficiaries in the past. So I think I feel more at ease on IB purely due to having a bigger screen and physical keyboard in front of me and that is why I use it for setup of beneficiaries.
The way the apps are setup and big screens on my cell phones(Primarily Samsung Notes), does make it very convenient to use though.
Capitec. The app is quickest for most of my needs - often faster than mobile banking - allowing you to choose to consume marketing when you need it. That said, I don't think all banks' apps are equally convenient and considerate on their platforms... more than one are a pure frustration to use with a terrible UI and marketing given precedence over functionality. They have effectively decided to paste a plethora of brochures on their teller window.
it depends on what I want to do. the full site is better for setting up things but once the setup is done the app works just fine for regular run of the mill payments and so on. FNB app.