There are no good or bad mutual fund categories. Every mutual fund category is meant for different kind of investor. Mid cap schemes are good for aggressive investors who want to create corpus for their long-term financial goals. Small cap schemes are good for extra aggressive investors who are ready to take a lot of risk to earn extra returns and create funds for their long-term goals. Both mid cap and small cap schemes are recommended to aggressive investors who can stomach lot of risk and volatility. Both the schemes have the potential to offer superior returns. Small cap may offer marginally higher returns than mid cap schemes over a long period because they invest in tiny companies that may become mid or large companies over time.However, you must choose your mutual fund schemes based on your goals, investment horizon, and risk profile. Focusing on return potential or risk element alone would be a mistake. Instead of that you should choose a scheme that matches your investor profile. For example, if you are a conservative investor, you should stick to large cap mutual fund scheme even though multi cap or mid cap mutual funds have the potential to offer higher returns. If you choose options that are not in line with your profile, you may find it difficult to continue with them when the going gets tough. For example, many conservative investors tend to panic and discontinue their investments when they see their small cap schemes losing money sharply in a bad phase in the market.We ask investors to take care of their investments on their own only if they have the necessary knowledge about mutual funds and investing. Otherwise, they are better off with the help of a mutual fund advisor. If you think you need some guidance and hand-holding, you should stick to your mutual fund advisor.