They are different animals
The Waterborne Impervo is an enamel
The Regal Semi-Gloss is not
The Waterborne Satin Impervo was meant to be a water-based replacement for the oil Satin Impervo (and Dulamel)
The Regal Semi-gloss was formulated on it's own
IMO, the enamels make great trim paint, whereas the Regal Semi-gloss make a better wall paint, and that's what I consider it
It's not that I won't use it as a trim paint if someone insists (on a latex semi-gloss), it's just that for trim I recommend the enamels
The waterborne Impervo does not care for over-brushing, whereas the Regal Semi-gloss will tolerate it more
When brushing, you will always get some brush marks
Personally and professionally, I prefer it that way
It shows it was done by hand the old fashioned way and not powder-coated and/or baked in an electrostatic oven or something
If one wants no brush marks at all there's always that pre-colored PVC molding