I’ve had both and they are actually very different. The Ecogold has grippy material on both the underside, and the saddle side. The ECP only has grippy material on the saddle side, with a brushed cotton material on the underside again the horse. So, it really depends on your needs.
That said, I no longer have an Ecogold pad, as I do not use them anymore because they do not hold up well. The rubber grip material along the front of my last one completely deteriorated with minimal use, and only occasional use of a breastplate. The underside, that was designed to provide non-slip qualities on the horse, because smooth and slippery. This was from less than a year of occasional use by an amateur riding only one horse (not a pro riding 6 horses a day), and being laundered as per guidelines in a washer with no agitator. They are expensive and I expected a lot more.
The ECP pad is nice and I really have no complaints. It’s not my favorite pad by all means but it fits multiple saddles well and has held up well.
My new favorite pad is Success Equestrian, as they make grip style pads in multiple shapes (to include XC), but they are a LOT more durable than Ecogold. The square pads are a lot more traditional looking than Ecogold but with the benefit of the breathable grip material. They aren’t the cheapest pads on the planet (cheaper than Ecogold), but I have two that have been used and washed a lot (probably 2+ years old), and both wash up like new.