The best mutual funds to invest in would be those that match your long term goals. The best way is to follow an asset allocation model. Every fund deals with certain asset class (large cap value, growth, blend), intermediate cap, small cap, and international. Another asset class in bonds (long term, medium, and short. Based on your age you should have that percentage in bonds ( 60 years old-60% bonds). Find the funds with the best long term record 10 years plus. You should be able to find this type of information on your web page where your retirement accounts are held.