<?php

$haystack1 = "(Job: NAS-Inkrementell) Operation succeeded. MyNAS-2 reports duty.";

$needle1 = "Operation succeeded";
echo preg_match_all('@(?<![\w-])' . preg_quote($needle1,'@') . '(?![\w-])@is', $haystack1, $matches1) ."\n";

$needle2 = "Operation succeeded.";
echo preg_match_all('@(?<![\w-])' . preg_quote($needle2,'@') . '(?![\w-])@is', $haystack1, $matches2) ."\n";

$needle3 = "MyNAS";
echo preg_match_all('@(?<![\w-])' . preg_quote($needle3,'@') . '(?![\w-])@is', $haystack1, $matches3) ."\n";

$needle4 = "MyNAS-2";
echo preg_match_all('@(?<![\w-])' . preg_quote($needle4,'@') . '(?![\w-])@is', $haystack1, $matches4) ."\n";