Time to re-analyze builds / perks / SPECIAL now that we have substantial play experience!
I haven't actually taken any level 10 perk myself yet, since my character's only level 10 stat is Intelligence, and I don't like Nerd Rage. But I think I've seen enough to talk about them.
STR 10, Pain Train: now that it's obvious that Power Armor is available almost from game start, the requirement to wear Power Armor doesn't seem like a big deal. Even though it costs Fusion Cores, my experience is that those are plentiful, and I've been hoarding them for no good reason.
The big issue with Pain Train is that it's essentially a melee attack. Maybe there are people who do melee in Fallout - I never do.
Perception 10: Concentrated Fire. +10% - +20% accuracy and damage for additional attacks to the same body part. Seems pretty decent, particularly if you get a VATS bonus pistol like the Deliverer. The damage bonus means it's beneficial even when you're at point blank.
END 10: Solar Powered. +2 STR and END during daylight, slow regeneration. The regeneration seems unimportant since healing items are plentiful. +2 STR could be OK if you were melee-focused, 1 perk point for +2 STR. Overall kind of underwhelming, though.
Charisma 10: Intimidation. I've been meaning to test this out. I don't know enough about how it works in practice to comment yet.
INT 10: Nerd Rage. SUCKS, because it only works when you're about to die, and the +DR is trivial. All too often damage will blow past the threshold, going from 21%+ health to death, so it won't trigger.
Agility 10: Gun-Fu. +25% damage to target 2, +50% to target 3, Critical to target 4 in VATS. Should be pretty damned good, particularly with one of those fast pistols I mentioned before. Sure, lots of times you're up against one tough target, but should make handling hordes of Ferals a breeze at low levels, when they're a real threat.
Luck 10: Ricochet: Not enough information about actual practice. Bugs me personally because it feels ridiculously cheaty and removes player agency. Enemies randomly killing themselves rather than because I did something is unappealing.