September's EU PSN chart is quite interesting. It seems a lot of people decided to buy PSP games which I'm guessing were on sale:
PSVita Top 20
Grand Theft Auto: Vice City Stories [PSP] (RE)
GTA: Liberty City Stories [PSP] (20)
Minecraft (6)
Metal Gear Solid: Peace Walker [PSP] (RE)
Resident Evil Revelations 2 (5)
Grand Theft Auto: Chinatown Wars [PSP] (RE)
Terraria (RE)
Sword Art Online: Hollow Fragment (15)
Danganronpa Another Episode: Ultra Despair Girls (New)
Manhunt 2 [PSP] (RE)
One Piece Pirate Warriors 3 (New)
Midnight Club L.A. Remix [PSP] (RE)
God of War: Ghost of Sparta [PSP] (RE)
The Warriors[PSP] (RE)
Tekken 6 [PSP] (RE)
Star Wars: Battlefront II [PSP] (RE)
FIFA 15 (1)
Metal Gear Solid HD Collection (RE)
Gran Turismo [PSP] (RE)
Titan Souls (RE)
The US one is a bit less remarkable though it looks like MGS 5 has sparked some interest in the older titles:
PSVita Top 10
Metal Gear Solid 3: Snake Eater – HD Edition
Sword Art Online: Hollow Fragment
Dragon Ball Z: Battle of Z
Assassin’s Creed III: Liberation
Minecraft
Borderlands 2
Hyperdimension Neptunia U: Action Unleashed
Danganronpa Another Episode: Ultra Despair Girls
Heroes of Loot
Ratchet & Clank Collection
Come on Rockstar, the EU chart shows there's plenty of interest in GTA on the Vita, at least throw us the iOS ports of the PS2 trilogy across now! I do wonder if Civilization and X:Com if they do come West could be a bit of a barometer for that.