Banty writes:

One penetrates; the other tends to sit on top and can get slippery.
I'd like the former and not the latter.

Better to understand them in terms of the technology than the purported
effects. And then demand specifics about how much material is going to
be applied. Don't let them wave hands about how good something is.

Your technical choices are between (1) asphalt-tar-in-water emulsion
with clay and sand fillers, (2) hot tar with no water, and (3) other
non-asphaltic stuff (acrylic or rubber) in a water emulsion and possibly
sand/clay filler.

They're all more or less paint. Nothing is going to "penetrate" and
renew the dried-out asphaltic concrete. The only way it could be
"slippery" is if you put so much on that you have a thick enough coating
to produce a flat surface.

Best performance and economy is hot tar, but this requires the most
equipment and other fixed overhead. Applying emulsions is basically
nothing more than painting.

All of the coatings are woefully uneconomical in getting material in
place for dollars. You are better off saving your money for repaving
with new thick asphalt at $$/ton than applying a paper-thin coating of
the same asphaltic substances at $$$$/ton. The illusion of value comes
from the cosmetics of having a fresh coat of cheap paint, at least for a
few days or weeks. Some people just want to believe a mere paint job
will extend the life more than trivially.