I think custom actions are easier to get right and be happy with. I think alot of gunsmith truing jobs are smoke and mirrors and who knows may even cause more harm than good to a factory remington. I think if you ever sell the rifle the public interested in buying the rifle also feels whatever truing was done may or may not have been good for the action. there is no standard for truing and not real way to measure it.
a custom action takes all that out of the deal and makes any potential resale value a lot better. with a custom action all the gunsmith needs to do is chamber and thread a barrel. with the proliferation of custom actions we are seeing alot more cottage rifle builders or companies that sell systems that sub out the builds and mark them up heavily. custom actions are allowing much of this to be done with good accuracy.
as for differences most are subtle and some not so, Surgeon and BAT are the only companies who offer a machined in scope rail and recoil lug. I personally think this is a big advantage. at the end of the day spending an extra 2 or 300 hundred on a custom action just ices the cake and adds a second kind of cool to your custom one that you can be proud of and others admire.
