Is al Hakims Hadith collection Al Mustadrak reliable?

Is al Hakims hadith collection Al Mustadrak reliable? I have read on Wikipedia that al dhahabi said it was better if he never complied it and ibn hajar was also dubious about it. al Hakim said about his book, that the sahih hadiths narrations are on par with bukhari and muslim? If al hakim grades a hadith sahih can it be trusted without verification from al dahabi abridgement of the al Mustadrak?