Does anyone have volunteer experience with Help Exchange?

Anyone who has had experience volunteering with Help Exchange, please post your comments about it. Their web site is http://www.helpx.net. There is also Workaway, http://www.workaway.info. Both these sites explain that you only need to work about 4 or 5 hours a day, with 2 days off and they will provide room & board. I plan on trying out both these sites when I finally start my ATW trip.