Been using Proplugs for ~20 years. They do have to fit right, and have to be inserted properly. I wouldn't call it a guarantee of a dry ear but they do a pretty good job.
Never used Pro Ear Mask. Have a buddy that did and it worked for his clearing issues. He improved his technique and sold it.
Another acquaintance is a very experienced diver but seems to have a fragile eardrum. On lengthy trips she would end up with a small leak in one ear. The Pro Mask seems to have taken care of that problem. Even easy "normal' clearing puts some stress on the eardrum. The Pro Mask seems to minimize that by keeping pressures equal.