I have done SBD off and on for several years now. I was a classic yo-yo dieter. What I like about SBD is no counting (calories, points, carbs, etc). And it is a very healthy way to eat.
I am maintaining. I can't remember how long that's been either! Probably a couple of years now.
Everyone is different but what I learned for myself, with my many years of yo-yo-ing, is that I really do have to agree with the cliche that this is a lifestyle not a diet. I reached my goal weight more than once and then would go on PH3 and probably considered that a license to eat what I used to eat. But if I eat what I used to eat I will weigh what I used to weigh. I regained time and time again.
Finally something clicked. And I have changed how I eat on a typical day. I stick with PH2 for the most part. But what works for me is to allow for splurges (PH3) for special occasions like eating out now and then or book club or.... And it took me personally a lot of time to learn how to have that splurge without letting it derail me and send me off on several days of binging.
Now that said, I would have to admit that I have learned over time that for me, eating will always be an issue. I have to make a conscious effort to eat well. I do best when I just don't have temptation in the house. So those splurges are never food I keep around. I don't do moderation well.
I have also learned that I feel so much better when I eat this way. Physically and emotionally. It is sustainable for the long term. After all this time I really can't imagine not following some version of the plan.
And that's probably way more than you wanted to know