I am a heavy drinker - coffee drinker, and I had lots of problems during my cruise on Coral last month. Firstly, the free coffee at Horizon was undrinkable. Yak. I mentioned this to the staff member who just looked at me and said nothing. Coffee at MDR was marginally better, not good, but drinkable. IC was a hit and miss, depending on who made it, but usually good.
Next time I will bring coffee mugs and some instant coffee with me to make a stronger brew to take away to my cabin.