Mine would have to be FraggleReef pink elephants. It took six months before I saw any growth. I started with two polyps last summer. Last month I had 4 polyps before I lost them. I have had two other morphs of pink elephant and both of them gave me at least one polyp per month.
Bam Bam Oranges and Cat Eyes for me. I finally got a baby on the Cat Eyes after about 9 months. I have two Bam Bam frags and one had gone back and forth between 2 and 3 polyps for nearly a year and the other has gone from 5 to 10 polps in the same amount of time.
I think for me it would have to be my RPE's. I have a frag of 4 polyps that have not grown any babies at all since I got them in January. They have increased in size and look nice and healthy...just no new polyps