Pillar bedding is the most expensive and works well with heavy barrels, full length bedding works for some guns but not for others, and doing a nice glass bedding on the action and chamber area with a fee floated barrel has always seemed to give me sub MOA groups with at least a few loads.
You will find that each method is good depending on the characteristics of the individual rifle. The best "gain to cost" choice would be free floating with a good bedding job on the action. Be sure to check the free-float when the rifle is cold and hot - wood can move a lot under the heat.
PaulS