Below we've listed some of the advantages and disadvantages to bear in mind as you consider which are best for you personal goals...

          US Gold Bullion Coins

          Advantages:

Most inexpensive type of US gold coinage (i.e., the American Buffalo and American Eagle gold coins).  Their value is closely tied to the spot price of gold.

          Disadvantages:

Although they are a good investment vehicle for those desiring to add gold to their portfolio, gold bullion coins generally are of minimal interest to the collector purists. Minted in huge quantities and typically bearing perfect strikes, these coins don't have much room for upward movement for their numismatic value.  They are and, in most cases, will always be valued primarily according to their gold content.

Given their scarcity, these coins are naturally less liquid than their bullion counterparts.  Their value is not tied directly to gold's spot price.  Rather, numismatic (collector) interest in these coins typically creates premiums for them that can be several times the value of the coin’s gold content. 

Rare Gold Coins

Advantages:

With ever growing demand and constant scarcity, values of rare gold coins have always risen higher over the years. Also, in 1933 gold coins that were deemed "collectible" received government exemption the confiscation that was taking place among bullion coins.  This has lead many to bet on the notion that if a similar government confiscation should ever happen again, rare gold coins would once again be exempted.

     Disadvantages:

Historically, they have not been as liquid as bullion coins, although the advent of certified grading has helped in this regard.  Collector demand usually causes the numismatic premiums for these coins to be several times the spot price of the coin’s actual gold content.