Great tasting coffee! Perfect for cold brew too!

My only regret is not buying more when they were on sale. My wife and I each drink a couple 12 ounce cups of coffee a day. I fill the k-cup, tap it on the counter a few times to settle the coffee, then add a little more. I definitely don't see a fill line, but I just use the rim as a guide. We have a Keurig K55 and have to push the small cup button twice.
I included a picture of the coffee in a bright window in a clear glass. This is after a 12 ounce brew, and you can't see through it. I love strong coffee, and these refillable pods produce it. I don't know why others are disappointed, but I'm not.
Update: We have been using them for a couple months now and they are still all working perfectly. I found the fill line too I think. It's at the top of the metal mesh inside the cup directly beneath the lid hinge.
I also recently find a new use for these!
COLD BREW!
I fill the k-cup to the line with no tapping or packing and I make sure the lid is tightly sealed.
I drop the cup it into my insulated 16oz mug full of water and refrigerate for 24 hours.
Remove k-cup, add ice (and cream if you prefer) and enjoy!
It has been hot and a nice cold brew is refreshing at work when it's 90+ degrees. I hope this tip is helpful.