Spider-Gwen, as she is affectionately called, is a fantastic new Hero to add to the stable. She shares the same stat line as Spider-Man and Groot, which may inspire you to put her into Protection with such a strong DEF stat.
Her effectiveness is derived from two factors: She is a Web-Warrior and she has an exceptionally powerful Hero ability.
"Free" readies are rare in this game outside of Quicksilver, and building for Gwen is a delcious puzzle. Here is a breakdown of Response/Interrupt Cards that are available to trigger her Ready:
Aggression:
(Responses) "You'll Pay For That!", Chase Them Down, Moment of Triumph, Surpise Attack (Interrupts) Skilled Strike, Mean Swing, The Best Defense
Justice:
(Responses) Brains Over Brawn, Lay Down the Law, Turn the Tide (Interrupts) Foiled!, Great Responsibility, Making an Entrance
Leadership:
(Responses) Moxie (Interrupts) Last Stand, Teamwork
Protection:
(Responses) Counter-Punch, True Grit (Interrupts) Defiance, Deflection, Desperate Defense, Expert Defense, First Hit (if using the second ability), Get Behind Me!, Leading Blow, Never Back Down, Pre-emptive Strike, Side Step, Stand Together, Subdue
Basic:
(Interrupts) Emergency, Warning (Even these old cards can see use!)
Protection has a ton of ways to allow Gwen to avoid damage and ready during the Villain phase. Aggression tends to provde cards that Ready Gwen during the Player Phase, with a nice spread of dealing damage, removing threat, and healing.. Justice has a decent number of cards, but you may find it tough to trigger the Events. Leadership is the most limited, only having a few specific-use cards.
Gwen herself includes 9 cards that can ready her in both the Player and Villain phases, so the consideration of how many additional Response/Interrupt cards may not be a prime consideration, but I wanted to list them for your consideration.
Givern Gwen's fairly consistent ability to Ready, she benefits strongly from boosts to her Basic powers.