HI Ett and welcome to the forum.
Actually if you type www.musicforum.co.za into your browser, you will end up here too! Norio and I are planning to move the forum in that direction very soon. And yes, there will be a dedicated keyboard and synthesizer section.
First take a look at www.ratcliffe.co.za/articles/buyerkey.shtml for a quick buyers' overview of the different features on keyboards.
1) Are these keyboards good?
They are alright for a beginner, It's hard to beat Yamaha in the entry-level price ranges, but if you decide to spend more and move into the next price bracket, get a Roland - the backup and service is far better than Yamaha here in SA.
It also depends on what you want to do. Firstly and most importantly, if you are going to take lessons, you must speak to your teacher before taking the plunge. Some teachers hate keyboards and will insist on an electric piano, with at least a 72-key or a full-range (88 key) keyboard and many will insist on at least weighted keys, freferably hammer action. If you are planning on learning classically, these things are essential.
If you are planning to learn to play "for yourself" then these "home keyboards" are great. They have everything you need, with built in speakers, headphone jacks, auto accompaniment and some teaching aids. Even as an intermediate step to playing with others and light gigging they can do the job within reason. On the downside, they may not have MIDI at all (for hooking up to another keyboard or a PC for recording purposes), or have a very basic implementation of it.
If you are planning on playing with others and gigging (or any situation where you are going to travel with the keyboard, then you have to look at stage pianos or synths, which are built a lot more robustly (but are in a much higher price bracket). Speaking of transport - if you are travelling with it (even if it's just in the car to and from the teacher), plan on spending a few hundred rand on a bag too.
2) Anything else i could look at instead? I'm really not looking to spend more than about R3500
I'm not as up on specific new models as I could be, but I'll check with a guy I know later to see what is on the market and what's best in that price range. I suspect that you are already looking at the right models though. As long as you avoid the Casio, Medelli, Technics and other models found in mass retail outlets, you should be OK.
3) As a complete beginner, would there be any point in me buying the E313?
Yes. It has layering of sounds (letting you play two sounds at once - like piano and strings) and split keys (which let you have a different sound on your left hand to that on your right) - well worth the extra budget just for that. A few other small features, but those are the important ones.