I'm really enjoying the 4 week meal plan (omnivore version). The recipes are simple to make and very tasty. I just finished my first week and lost a few pounds on it even without a workout at the same time. It's really helpful for me mostly because it really teaches portion control and gives you a solid idea of how much protein/veg/starch you should be eating. The meals are also pretty simple to make, which is a must for my lack of cooking skills.
However I've observed the plan itself (the PDF) has frequent errors. It really needs for someone at FB to follow it exactly, not just glance over it. I'm the type of (poor) cook that follows lists and recipes to the letter, and I don't have a store of random things in my pantry to draw from; I depend on the lists and recipes to be right. For example, week one grocery list includes "Plain Whole Milk Greek" as one item, and Yogurt as another (each with its own check box). Greek Milk is called Kefir (as I learned) so I bought it. During the week you realize those were meant as one item not two, so the Kefir went down the drain and I had to sub for the yogurt. In week two, Day 8 calls for Lasagna noodles and Day 9 calls for walnuts and sunflower seeds, and none of those items are anywhere on the grocery list for that day or any day. Until FB reviews this plan I'd recommend you spend time each week going over each day's items before you shop or you'll end up going out again or wasting some items. These are just examples from the first 8 days, there are more.
I'd also say that if it weren't for COVID and working at home, this plan would be largely impossible to follow. It frequently requires the oven or stove top and often has meals with lengthy cooking times for lunch which is impossible in an office environment. Reheating for some items is just not a good idea so you'd end up repeating days to avoid the need for cooking at work. I suggest that FB consider providing a "workplace" alternative to some meals for those who are not at home during lunch.
Overall it's really a nice plan and I'd recommend it to anyone who wants a structured nutrition plan; just watch out for the observations above.