My friend swears by hers, a Tefal one, but she has had it since she got married so possibly that model not available any more.
I borrowed it recently, and although it's fairly useful and does have the "keep warm" function, I still had to keep an eye on it like I would if I was just making it in the pan, and a large section of the rice at the bottom was inedible, so quite a lot of waste. If you need to make a large-ish quantity, then you need to put it on tea towels and so on as it bubbles over.
Also, it doesn't seem to automatically go from "cook" to "keep warm", I had to switch it over. This is probably why the rice at the bottom was inedible, I was waiting for it to automatically go from one setting to the other, but it didn't, so i switched it manually.
Other models may be better than this, but to me, it's a very large piece of kit to store as well, when frankly, you can use any pan that gets used for everything else anyway and easy cook rice is just that, damned easy!