This seam sealer is highly recommended so I got it to use on my tent. The brush is useful, but take note, the liquid is like elmer’s glue, but more runny so even a few drops will follow gravity quickly. As such, make sure the brush is always facing down, just above part you want to run the sealer over. Trying to do it sideways or upside down is laughably impossible as the liquid just runs down the bottle. Best way is to turn your tent inside out to seal the inside seams.
As for quality, it comes highly recommended, tho I won’t know till I field test it.