Active investors who pick stocks for themselves face a challenge when also investing in mutual funds.
On one hand, if you buy mutual fund that invests in the same vein as you do, then either you are acknowledging that the manager is better than you - and you should not invest yourself, or they are worse than you are - and you should not buy the fund.
On the other hand, if you buy a fund that invests very differently from you, then either you don't trust your own investing method and his method is better - so you should not invest yourself, or he is worse than you are - and you should not buy the fund.
I have invested in funds such as IIF, TDF, IGE, TAVFX and others. Looking at the stocks they hold... I would have probably bought very few of them.
One positive way to look at holding mutual funds is to consider areas where you want to invest. If you you don't have an expertise in one of these areas, then it may be worthwhile to buy a fund in that field and assume that its manager is an expert. This was my reason in investing in IIF and TDF. Another reason is when the mutual fund can buy securities or bonds not easily available for retail investor. It is becoming easier and easier to buy even international stocks directly, but some funds still have access to markets and securities not easily reachable by individuals.