To measure fees you look at the expense ratio. The expense ratio is the percentage of the total assets of fund that is deducted each year to cover all the fees. Therefore a high expense ratio indicates that the fund is deducting a lot of money each year from the fund's assets to pay for commissions, advertising and management fees. The thing that drives these funds, or rather that drives us to them, is how much money we can make. High return means big bucks.
Funds can lose money or more than double it each year.
Some technology funds have had astronomical returns over the past few years. I have spent a lot of time thinking about this stuff lately, but I'm still new at it. If I am going too fast please stop me. Write to me about it on my boards . If you think I am making a big mistake, tell me that too.