To me, this one looks more succinct, if a bit too much on one line ;-) But, to take this a bit further, I look at postfix "if" as "grep" ...

print map {
  "$_\n"
} grep {
  $_ == sum map { $_ ** 3 } split //
} 100 .. 999
[download]

IMO, both better (more whitespace) and worse (hiding the loops, removal of parenthesis for the sum function). ;-) (I'm sure others have their own opinions of how they compare.)

Just to make it a bit worse ...

print "$_\n" for grep {
  $_ == sum map $_ ** 3, split //
} 100 .. 999
[download]

Or is that better? Hmmm...