It's interesting reading the above threads the different ideas people have of what makes a folk 'festival'.

To my mind a festival brings together all the different strands of the genre, eg dance, song and instruments which would rule out a fair few of the gatherings mentioned above.

Given my interpretation of 'festival' I would nominate Saddleworth and Cleckheaton as not only friendly but extremely good value.

However, I do tend to go to more informal weekends which I think are the most special.