There are several good feature of the 401K is employee funds are taken before the tax on your salary. The 401K plans are transferable. The 401K plans are built up on the common objectives of the employer and employee to give the benefits to the employee when they get retired. The certain amount of money will be transferred to your 401K plans from your salary account before tax paid by you.
Apart from good security and the safety of your money there are certain risk factors. The risk is based on the selection of the types of fund. If you are invest your fund in the stock market. It is highly instable. It gets change every time. If you select foreign exchange it will add more risk and that will affects on your return. You may gain good return and some time less depends on the market situation. If you invest money in the bond market then you might get better return if the economy is good and inflation is under control. If economy is not good than you might loss, so higher the risk you might get better return. I think investment of fund in the bond is less risky as compare to stock market.