The following has significant Throaty Mermaid spoilers:
Another of my players tried out a Vigilante this weekend, this time an Aasimar* Zealot (Celestial Divine Power.) I forgot to ask for his exact build, but he had a high strength, high charisma, and a reach weapon. As the entirety of the Scenario was on a small ship, the Vigilante opted to stay in their Social Identity for the duration of the scenario.
As the name might imply, Throaty Mermaid is a Murder Mystery, a scenario that I thought would be right up the Vigilante's alley. Before the investigation though, there was an initial combat with a team of boarding elves. The combat was fairly unexciting, with the Vigilante performing reasonably (high strength + 2 handed reach weapon = dead elves.) Post-combat, the Vigilante's true role in the scenario began, the Diplomancer.
Me: "Ok, so even though they started off Hostile, you insulted the elf's heritage, and intentionally aren't speaking in their language... yeah, a 28 plus assists will do it..."
With the +4 Diplomacy from Social Grace, a decent Charisma, and Diplomacy as a class skill the Vigilante had over a +10 to Diplomacy and easily
steamrolled the Diplomacy DCs in the scenario. It actually became somewhat of a running joke, where during interrogation of a suspect there was the following exchange.
Me: "Ok, with that Sense Motive it seems like the suspect is hiding something. Can I get a Diplomacy Check to find out what?"
<Vigilante Player, who wasn't at the table at that point and didn't hear the question returns>
Cleric: "Vigilante, you're up."
Vigilante, not even asking what he's rolling for: "I got a 30 for my Diplomacy Check."
The Vigilante's other skills came up occasionally, but other players had higher skill modifiers (The Oracle had a better Intimidate and the Sacred Fist had a better Perception and Sense Motive.) Overall they made short order of the investigation and proceeded to the final showdown.
I had one small modification to the final encounter as written: the Murderer's accomplice used Charm Person to turn a crew member against the party so there were three opponents against the party of four. That was short-lived, however, as a Cause Fear neutralized the extra NPC for a majority of the encounter. This turned the combat to be fairly unexciting again, as a Support Bard with a negative strength and a Rogue NPC duo didn't have much they could do. When it looked like the rest of the party had the combat in hand the Vigilante switched to trying out Heavenly Fire, which was somewhat underwhelming. With 1d4 points of damage on a touch attack, he would have been better off just attacking with his weapon. Also, luckily the Accomplice was actually Evil; there were several Neutral options and they would have just been wasted targets.
Takeaways:
At level 1, the Vigilante doesn't have a real compelling reason NOT to be in Social Identity, which I hadn't really considered previously. With the +4 to a skill (Diplomacy, Perception, or Use Magic Device are choices I could commonly see), it seems like a no-brainer, especially given that Vigilante Talents haven't come online yet.
The +4 bonus from Social Grace feels a bit high for a 1st level ability.
Heavenly Fire is underwhelming. It's neat in that it can be a modular ranged damage / healing option, but it's a bad use of a standard action in most situations. The fact that it doesn't even impact Neutral Characters makes it almost unusable.