It took 150 days from filing to USCIS approval, but this is abnormally fast. I think the average seems to be about 1 year at this stage, and from what I gather, the beneficiary's country has no influence on this stage. My interview is scheduled for November, so it would be 269 days start to finish. How fast the NVC/Consulate part goes really depends on how quickly you get all your documents together, how fast the NVC are taking to look at them and whether they request more evidence (that only took us 9 days, which is super fast), and how backlogged your consulate is (luckily London is fast, but I hear some have years worth of backlog).
Hoping for a smooth process for you when the time comes 🤞