I think most of the custom action makers are heavily invested in expensive equipment and therefore make actions that will sell to a clientele that sometimes seems a little slow to accept or embrace "new things". Discussing the merits/demerits of the equipment we choose to use seldom makes much sense.
I have spent 12 years shooting about that many Savage or Savage-based rifles and find them to be great shooting platforms. A factory Remington M700 is no competition to a factory Savage M12 say nothing of the LRPV or Target action. Unfortunately, factory Savages have priced themselves into the area where they are competing with brands like Cooper, Sako or even used customs and their build quality is not there. Even at that, if you do lots of shooting, change barrels, change calibers, etc., the Savage is still a better platform because of the ease of changing main components.
I also have several rifles with custom or customized actions. There is no question the new custom actions we have to choose from are the best ever made.
Getting away from brands, models, etc., I believe that a "floating" bolt head is pure genius. Once the bolt is closed and the lugs are seated, the rest of the bolt does nothing except house the firing pin and supply a handle to engage/disengage the lugs. A floating head is divorced from any stress or pressure from the rest of the bolt. The lugs need only align themselves with the receiver and not the whole bolt handle. Then, the ease of changing to a different caliber head size gives you a flexibility that's very inexpensive.
The barrel nut method seems to be quite a bit of genius to me, also. With a trued receiver and trued nut, a pre-chambered barrel can be installed, uninstalled, reinstalled. I can buy a "pre-fit" barrel from several suppliers or even used and install it on my Savage action without any problem. If I buy a barrel off someone's M700 or BAT, it almost certainly won't fit my action with proper headspacing without a gunsmith doing it. I've heard that some of the newer Panda's are that perfect, but haven't seen it in reality.
There's very little prestige in showing up at the bench with a Savage-based action in today's world and that still has lots to do with what we shoot, or drive, etc. I understand that. But that doesn't mean the concepts Savage birthed in it's action aren't viable. IMHO the Savage actions are butt-ugly to look at. But I'll let you know in the spring if my 30 BR on a Savage action will shoot with my BAT SV. I'm curious to see for myself.
If I want to change my Savage from 6 BR to .223AI (which I do periodically) it only costs $68 for the second bolt head. In my BAT, a new bolt for the new caliber is $475 (which, by the way is about the price of Savage Target action).
Long-winded thoughts ...