It's the way the GA team present themselves.  They seem to care more about entertaining and proving what they already believe with frequent paranoid reactions than going in with a skeptical approach, something the TAPS team do.  Whether or not GA or GH are legitimate or not is besides the point.  Both could be utter fakes when it all comes down to it.  My point is that the TAPS team just appear more believable based on their approach to the subject and the way they carry themselves.  A television show is a television show, and based on my personality and preferences, I find TAPS much more interesting and convincing.  This is my personal opinion and preference.

Regarding the location and saying about how a place like Poveglia Island must be haunted, is really suggesting it is a prime place for a haunting based on it's history.  Now I have researched this place and I know the facts and folklore behind it.  But if the folklore is true, then the place has a brutal and tragic history which if anything would probably leave behind residual hauntings.  Do I know this for a fact?  Of course not.  But it's probable, if you're the sort of person who believes in this kind of stuff (which I do, but I take it with a grain of salt).

All I am saying is, if GA is legitimate in their findings, they sure have a funny way of trying to convince me (the viewer).  It's hard to take their reactions seriously, especially Zac's "posessions" which I am to no end skeptical of.  If I don't trust that, how can I trust anything they find?  Great entertainment, but that's all it is, at least for me.

Another reason why I enjoy TAPS so much, and what makes them more convincing to me, is the fact that many of their episodes are flat out boring.  Why?  Because they do, in fact, visit places where they haven't collected any (or very little) evidence.  They don't need to pretend to have personal experiences, if they genuinely haven't had them.  I like this, because although it's not fun to watch, it seems more in line with actual ghost hunting (you win some you lose some).  Again, I have no proof of anything TAPS has done, but if they were all about making every show as entertaining as the last, and going at any lengths to do it, they would have lost my respect a long time ago.  Plus, I just like the calm personalities of TAPS investigators compared to the paranoid, over-excited and jumpy GA team.