How to find a reputable place for a meditation/health retreat? [closed]

I am looking for a meditation and/or health retreat in Europe, but have heard some "horror" stories from friends (horribly overpriced places, bad food, crappy teachers, etc.).I'd like to find a place far from the city, with decent facilities and good teachers, but don't know where to begin.

Would Yelp and similar be trustworthy enough to judge the quality of a retreat?
Are there forums, groups, etc where I could find accurate information on the subject?

How to find a good place to practice meditation (or yoga, or Pilates, etc) for a couple of weeks?
And how to know if a place is actually good based on online resources?

Note :
For now I'm looking for resources and advices to help judge the quality of retreats beforehand, not for specific recommendations.