>>416
You can safely skip Boogiepop Phantom. I watched it a few years ago. It had great music IIRC, but its easy to tell that the story they adapted was taken from the middle of things so it was quite confusing with little to no answers to questions that come up.

Boogiepop wa Warawanai is an adaptation starting from volume one of the source material. And feels very cohesive and well done. Questions get answers eventually, though the non linear nature might throw some people off, but that means a rewatch will be all the better. I would definitely recommend watching it.