New bathroom tile is 8 x 16 oversize subway tile. Tile store sells Flextile grout - has anyone had experience with this brand? Here's info from their website.

500 Polymer Modified Unsanded Wall Grout

Flextile 500 Polymer Modified Wall grout is a premium Portland cement-based grout containing finely ground fillers, colourfast pigments, and polymer additives to provide superior flexural and bond strengths

For grouting all types of ceramic wall tile, marble, glass mosaics or mosaic tile where joints width is 1.5 mm (1/16") to 3mm (1/8").