Acrylic grouting is smooth /sanded surface and slightly gloss looking.
It is a complete replacement of the existing grout lines with a hybrid solution that is capable of withstanding most chemicals and does not have epoxy flake problems/ water mark issue
It is mostly used for residential as is it aesthetic pleasing
Recommeded, best grouting on market currently
Epoxy grouting is rough surface with matte finishing. It's the replacement of existing grout lines with sanded epoxy grout that is traditionally used in swimming pool grouting and therefore the toughest available product on the market.
Grout sealing is a layer of sealant/protection on the existing grout lines
Marble Glue is a completely different genre of product, it's used for surface of the whole floor and tile and requires specific expertise and products to work with.