I find it funny that the bad review are from people who are looking for entertainment and a good scare. As far as real investigations go, they're doing more than going in with fancy tools and a 'good story' to say 'yes it's haunted' or 'no it's not' - they're taking the time to truly investigate the background, the people, looking for corroboration, approaching each situation with a plan, they know their limits and seek help and advice from professionals and all with a goal of helping people. Oppression is what happens when a demon can't possess you. Either that person has a lot of prayer surrounding them for protection, or their home has been protected or blessed, or they are saved. Since the demonic force can't posses you, they affect your life by oppression, using outside forces to weigh you down, harass you.
I think it should be a warning to anyone out there who dabbles in the occult on any level. It doesn't have to be deep black magic or witchcraft and summoning rituals... it could be something as seemingly innocent as recording activity.
Seek and you shall find... be careful what you wish for... no matter which way you put it be careful. You don't know what you can open yourself up to and worst, you can release something that will bind itself to you and follow you.
the problem with seeking the truth is that sometimes you find it...