Here is the ratings system I use on this site explained in more detail. I currently use these ratings for Wine and Coffee.
★ – Not zero, but this is not going to win any prizes.
★★ – Not the end of the world, it’s entry level, satisfactory.
★★★ – More than satisfactory, does what it says on the tin, you’ll be happy.
★★★★ – Excellent, well worth it, tastes great.
★★★★★ – Outstanding. Buy this. Must have.