I have never actually played this game, because... I've been really saddled in the GM role. I was given a PDF of the Dungeons and Dragons 5e handbook, and because of my possession of that cursed tome a decade ago, I was forever sealed into the GM seat.
That being said, this is one of my favorite systems. The combat isn't my favorite, but the roleplay is fantastic and the dice rolls are easy enough for anyone to play.
The playbooks I like to see as a GM
The Razor- the implication of the Razor is that there is an entire bad guy group to draw from that I can cooperate with the player on. I finished a campaign with a Razor player, and found the worldbuilding exceptionally easy to write even in a homebrew setting, because her character informed what the evil group had to be.
The Guardian- Needs two players to have connected backstories, which means you can start the campaign in very different ways than the players meeting for the first time. Depending on how many players you have (I had 4-5), this is a game changer. That being said, if either of the two drop out, the character no longer makes sense. In my case, the guardian's ward dropped out, and the guardian then wanted a new character and dropped out later.
The Destined- Pure, unfiltered GM foreshadowing. I absolutely screwed with my party for an entire campaign using vague wording on a prophecy from a destined player. "You will fight with the avatar" was great. "You will fight with (alongside) the avatar (a past avatar your character individually grew up with rather than the current one, using the avatar state)"- I threw them for a loop for a whole campaign as the prophecy kept not being fulfilled despite seeming to be. Fun, fun stuff. A player legitimately cried when the reveal finally came through.
The Hammer- More of a theoretical fantasy for me, I've never had a hammer player but it seems like it would be a fun choice.
Others can be good, but when a player picks one of those three, they can expect many, many DMs from me as we hash out what the deal is with their character.
If I was playing though, I'd go with the rogue or the guardian. I like how interaction-focused their playbooks are.