After a quick search, I came to this:
"In "development tests," which are designed to see if the technology works on the most basic level, the new Patriot did very well, hitting 10 out of 11 targets. However, in "operational tests," which are supposed to simulate real combat, the missile did much less well, slamming into the target in fewer than half the engagements, due mainly to computer glitches."
"The Army did not respond to repeated requests to comment on the PAC-3's record in trials. But an official at Raytheon said Coyle and others didn't understand what the tests were designed to do.
"What we were testing was the entire system, not just whether we could kill a target at the end," the official added. "The end game may not be to intercept the missile.""
Well, if I were Polish, I wouldn't feel very safe after reading this