McMillan has a craftsman who does nothing but bed rifle stocks. His work is incredible. Other folks can bed stocks very well and their prices are lower. The process used at the McMillan factory is different, he beds from the rear of the tang to the front end of the barrel channel. He has access to factory stuff and procedures that other smiths don't. Beautiful work that has to be seen to be appreciated. If you want the best this is one way to go.
GA also has a bedding specialist that does excellent work - Eric's work is acclaimed as being exceptional. Building sniper rifles for the Marine Corps obviously gave him good experience! My rifles bedded by George himself are not too shabby either...
Bedding a stock is not really rocket-surgery but some guys just do a better job than others.
The smiths here can tell you what full inlet means - I have only custom drop-ins and have one complete installation. Custom drop-in is just that, the stock has a recoil pad installed, is painted and CNC inletted to fit your action and trigger-guard assembly. This is the stock most guys buy, your barreled action will drop-in and the rifle will shoot well. McMillan suggests shooting as is, then if the bedding area compresses or you are not happy with your accuracy have a pillar bedding job done. I have had rifles shoot incredibly well as drop-ins, but in the long haul you are best to get the action pillar-bedded in Marine Tex or SteelBed. The barreled action is not going move, your accuracy will be constant day in and day out.