I can't really compare it with Optimum stuff as the only Optimum product I've used is OP.
I've only used H-T EC with foam pads (no wool).
I find that the H-T EC slots in-between two of my 3M PI-III RCs- it's a bit more aggressive than PI-III RC 05933 but it's milder than PI-III Extra Cut RC 05936.
I do really like H-T EC, it's effective without being "liquid sandpaper"-scary (the way the PI-III ECRC 05936 is). I've used it straight, mixed with a *little* OP, and mixed with a bit of 1Z Ultra/Extra; each of those three methods worked well, with subtle differences between them.
I would *not* mix too much OP with it, it seems to dilute the cut a bit too much while not offering any benefit over adding just a little. A *little* OP will increase the work time (as did the 1Z Ultra) but IMO with a bit of familiarization you might find that the H-T EC works fine by itself. I've gradually gotten away from adding OP to it and I don't seem to be having problems with the work time being too short. You might oughta add the OP if using it by PC/Cyclo/etc. though, as the longer work time would probably ensure more thorough breakdown of the abrasives.
As with most aggressive products, I'd use it with a cutting pad and yeah, you'll need a follow-up with a milder product/pad combo.