The s-300 system is fine but no match for modern air forces like the Israel's and the West . The much-vaunted requires even more intelligence and countermeasures if you need to defeat it. It won't be easy. The US has a few S-300's on hand, so I would expect any countermeasures to also be in Israel's capability.
UN to hold off on separate Afghan bombing probe for now (Reuters)
from the article: Lebanon warns UN: Israel planning to attack us