Having battled with a Dremel for a while, I'm thinking of investing in a Foredom motor.
I understand the SR goes to 18,000 rpm, and the LX to 5,000 rpm.

From my research so far, the consensus seems to be: "if you're not sure, most people go for the SR".

However, isn't 18,000 rpm way too fast for most jewellery work? I would have thought 5,000 rpm is plenty for drills, burrs, and so on? Hence I'm leaning towards the LX.
So why does everyone go for the SR instead of the LX?

Can the SR be controlled at slow speeds too, for burr and setting work? If so, what's the point in the LX?

I would love to hear opinions on all this. Many thanks!