[trainchain]

What are the merits of this training aid over the speedstik?

Not to mention the swing mechanics benefits, but from a pure speed standpoint:

The speedstick, momentus, and weighted clubs are isotonic or "dead weight" devices. Meaning when one swings them, on the downswing their own inertia plus gravity is assisting on the downswing. They are probably ok for strength but not real effective for speed IMO. They also fail to meet the 4 laws of specificity for speed training.

Contrast those with the SC. The SC is a variable weight resistance device which provides an overload/resistance on the crucial start of the downswing and thru the impact zone. And it can be swung extremely fast. Much faster than weighted clubs and the speedstick. It is the only training device I know of that meets the 4 laws of specificity for speed training.

Hope this helps.