Protective Headgear Questions

I have never been a big fan of protective headgear unless used by those who have already sustained some type of concussion or head injury. That was until today.  One of my daughters was playing goalie in a scrimmage today for her academy team.  She dove to block a shot and hit the side of her head on the ground when she landed.  It hurt her bad enough to come off of the field.  One saving grace was that they were playing on grass instead of turf.  She was okay after a few minutes but it started a conversation with me and my wife tonight.  My daughter only plays goalie every once in awhile.  This is mainly due to the fact that she helps her team out more playing in the field instead of at goalie.  However; when she does play goalie, she plays very aggressive and shows almost no fear when challenging for the ball.  My wife and I have decided to get her some protective headgear for the times when she plays goalie.  We might even have her wear it all of the time if it is comfortable.

Does anybody have any recommendations for headgear that they have purchased.  There seems to be quite the variety available.  We have seen the kind that looks like just a heavy duty sweatband al the way to the ones that look like a small helmet.  I would love to hear from anybody who has an opinion good or bad on any of the available headgear options.