MDX or MDXX has a very, very bitter taste. You will wince and your eyes will feel like closing as you chew it. The bitterness is very dull almost metallic sort of. It is not the bitterness of a lime type taste for example which is a sweet type bittnerness.
'Typically the pill (if you chew it up) will be a smooth consistency and will sort of like melt as you chew it. I had a pill two weeks ago (piece of shit lime colored green pill with a christmas tree logo on it) that was fairly bitter when I pressed the edge of it under my tongue, but when I chewed it up it broke apart (wasn't a very smooth consistency as I chewed it) and it wasn't all that bitter.
It was a total dude and I felt nothing. Maybe there was 20 or 30 mg of MDX or MDXX, but It was a dud.
A good pill should be so bitter that you'll want to drink something ASAP. You'll also have the feeling that you'll never want to chew it again because it tastes so bad. If it is a good pill though you'll want to chew a couple every two weeks though, lol.