The rear lug receiver will vastly increase the lug surface between the receiver and the bedded stock. Bedding is used to keep a consistent tension on the the receiver/barrel assembly. In an unbedded rifle assembly the tension on the receiver/barrel assembly varies due to the shifting of the receiver/barrel assembly in the stock. The variation of stresses on the receiver/barrel assembly from shot to shot produces inconsistency in point of impact. Hence, most tack driver rifles are bedded. The question to be addressed really should be will the average shooter ever notice the difference due to the advantage of a rear lugged receiver in light of all the other variables that come into play with pin point accuracy shooting? For the competition shooter that shoots thousands of rounds per year the answer is most likely yes. For me, with my level shooting skill and frequency of shooting, the answer is no. In addition, it would be hard for me to justify the additional cost.
For an example, The FN SPR rifle I have still has the standard size lug on it that it came with. Many precision shops will modify your rifle for you and add a extra large lug to it. The rifle was sent to GA Precison for a beautiful bedding job but left the lug OEM stock. When I do my job, it performs very well and I'm very happy with it. How good is good enough
Just my $.02 worth