For me, Ark is the most interesting one. I have been following it for some time, it seems to me that it has great potential. Pivx and SysCoin are new to me. I will definitely look to it, but Ark is my favorite. I already made little profit with Ark in the last spike and waiting for next wave.
And it continues to perform in line with the others - back to new recovery highs today.
That's why it is my favorite. I know it will never let me down.