I'm very happy with my KO PDS 2123.
Personally, I find that a steering servo cant be too fast
So I'll recommend you get the best you can afford. If you go with good brands like KO, Fut, JR or Air, you'll probably have it for many years.
Analog servos can be as fast and strong as digital ones. If I had to choose between a slow digital and a fast analog, I would go analog. Ultimately, get a digital one, if budget allows it. Digital ones have better resolution and way more holding power. They are also stronger around the center, than analog ones are.
For EP cars, there's no need of programmable servos.