You don't need to spend alot of money to make perfect SCD yoghurt. what's really important is the TEMPERATURE being accurate and stable, and the TIME you allow it to ferment/cook.
My husband (who is a bit savvy with electronics) made me an SCD yoghurt maker out of a rice cooker and PID controller (FYI- http://en.wikipedia.org/wiki/PID_controller
). I make the yoghurt in a stainless steel cooking pot suspended inside the rice cooker.
Re: The taste of 24hr yoghurt. It is just like 'natural yogurt' with no added suger and stuff. So it is fairly tart, a bit like sour cream. However once you've made your yogurt, you can add a little honey or your favorite fruit to sweeten it up. :)