I'm not a ramen ace. I've had some here and there, and I'm aware of general materials and methods involved, but I've not been to Santa, Halu, or other reference standards. My level of appreciation is informed by personal taste more than vast experience and knowledge. Nonetheless: if there is good soup to be had, it's worth telling others about. Which brings us to Lava.
They do a variety of noodle dishes, but I've only had their ramen. The lava broth and miso broth are both rich and balanced. Noodles (wrinkled) are firm. The onsen egg has a consistently excellent yolk texture and good flavor from a shoyu bath. Chashu pork is flavorful but varies in tenderness. Meat portions are a tad small, but otherwise topping quantities are reasonable and balanced. Everything is served appropriately hot, i.e. scalding.
Non-food summary: wait: usually little or none to be seated, but modest wait for food; service: efficient on a good day, brusque and inattentive on a bad one; environs: appealingly modern and comfortable; noise: good considering the rather dense seating; price: what one expects to pay for ramen, i.e. $8.50-11.00.
I wish I could provide a more nuanced review, but for now hope that this will encourage others to try and provide more opinions.
Lava Restaurant and Lounge
527 Bryant Street
San Francisco, CA 94107