[stanis@home ~] % cat a.php                                                     [3:08:57]
<?php

$str = "something'that'should'be'escaped'";
$starttime = microtime(true);
for($i=0; $i<10000000; $i++) {
  $a = base64_encode($str);
}
echo $a, "\n";
echo ((microtime(true)) - $starttime), "\n";
$starttime = microtime(true);
for($i=0; $i<10000000; $i++) {
  $a = addslashes($str);
}
echo $a, "\n";
echo ((microtime(true)) - $starttime), "\n";
[stanis@home ~] % php a.php                                                     [3:09:05]
c29tZXRoaW5nJ3RoYXQnc2hvdWxkJ2JlJ2VzY2FwZWQn
1.6811218261719
something\'that\'should\'be\'escaped\'
1.9145817756653