I've been on the Durban / Cape Town (and back) route and used Shosholoza Meyl to do it. Yes, it's no Rovos Rail or Blue Train but it's not their prices either.
I can thoroughly recommend it as a method of travel across South Africa.
The railways in SA go through a lot of towns that used to be coaling / watering stops for the steam engines. With the change to electic / diesel most of these small towns took a nose-dive and so are now not exactly pretty. Other than in major cities where Metro-rail still run commuter services, stations have become derelict.
As an small experience in industrial archaeology though they're quite interesting. And, there are still a good percentage of towns that have mantained their charm.
Other than the eastern coast, the Drakensburg of KZN and the wine and fruit growing areas north of Cape Town South Africa's landscape from a train can seem boring. The vast expanses of the Karoo that the Jo'burg / Cape Town train goes through are, in my opinion, best travelled by anything other than a car, preferably with a good book and a drink (or several) close nearby. The train's ideal.
Only once the train gets to the Hex River Valley does the scenery get worthwhile but, unfortunately, the timings of the train mean these are done in the dark of early morning or late evening. I believe that Rovos Rail make a point of travelling this part in daylight and even stop at Matjiesfontein which is an historical tourist stop in the middle of nowhere on the Karoo (but an interesting history as fas as steam trains and the local farmer's water supply monopoly.)
These tourist trains can suffer from delays caused by (for example and not frequent) rail freight derailments. As long as you allow for these within your further travel arrangments it's fine.
A major part of your decision will depend on where you want to be at the start and end of the train journey and what you want to do when you get there. Or, you may be thinking of using multiple train journeys to get between the tourist spots.
Cape Town to Port Elizabeth by Shosholoza Meyl has recently been added as a route and goes through some rugged scenery.
Durban to Cape Town is scenic to begin (KZN and the Drakensburg area) and end (Hex river valley / winelands.)
Read my review (link below) and, if you want more in-depth information, send me a personnal message.
I've also given a link to Shosholoza and Premiere Class within Spoornet.
tripadvisor.com/ShowUserReviews-g293740-d543…
www.spoornet.co.za/Website/passengers.html
For prices and bookings I'd recommend contacting Santie within their web site at:
www.satravelbooking.co.za/