Having been to both types of sessions in Halifax, they're both good. One session was just for the pure love of music, and no one got paid. The second one, the host got paid, and the singers/musicians got the first beer free. (Think they got a break on the price of the beer later. I drank Sprite, and there was usually a break of some kind).

Music flowed in both. The first session was designed to be in a Non-Smoking venue, and everyone loves it. The second is in an Irish Pub environment so you have a lot of patrons who are talking over the musicians.

Hard to say which is better.

I do think that the host of the session should be paid something, whether it is in kind (ie beer) or $$!