I can vouch for three of those. Haven't been to the first one in Koreatown, but I will go this week or the next and report back. Father's office used to be my favorite burger in LA and it is still great, I'm sure, but I refuse to go since they bumped the price up to $20 for a burger with fries. That's just getting out of hand. Plan check is where it's at and their chicken sandwich is unreal too. I could list about a dozen other places in LA with amazing burgers, there are so many good ones. The burger scene here is serious and it's so much more than just In-N-Out, which is what I feel like outsiders think of a burger un LA. Burgers here remind me how Pizza is to NYC or hot chicken in Nashville or Steaks in Philly, but not quite on such a historical level because I believe its only taken foot in the last decade or so.