I love both. If I had the choice between an awesome flame and an average quilt I would take the flame. If I had the choice between an awesome quilt and an average flame I would take the quilt.
Quilt tops can be beautiful, but they can be creepy too - I've seen bookmatched ones that look like they have faces in them - gives me the willies.
Flame is nicer IMO, but it has to be done right. If there's too much difference between the two sides it looks schlocky, and if it's too perfect and symmetrical, it looks strange too.
For an unpainted guitar I actually prefer the grain to be visible, but subtle - like Page's old LP standard or Fender sunburst strats.
That flame silo is georgeous, though. I'll admit that I've played a few JPs, an Axis, a Luke, and a Benji Madden, but never a silo.
I've got my fingers crossed that the JP goes in that direction and is offered in a flame top. Maybe a 5th anniversary JP? (hint)