I have. I had something like 50-30% adherence to it during June-September, something like adherence 4 days out of a week from October until the start of December, one month off during December because of family obligations and then mostly bulletproof from the new year onwards, with me ordering the coffee and everything. I would say that I go "off" the diet about one meal per two weeks, but as much as possible "slightly" (for example, a single meal with enough rice in it to take me out of ketosis).

Since I've started the diet, I've also made other adjustments, such as striving for at least seven hours per night, scheduling my time better to reduce stress and not going hungry because I'm too unmotivated to make food. Keep these in mind on top of all the other 'wacky' self experiment biases. (Alternatively I CAN PRIME YOU TO ASSOCIATE ME WITH LOW STATUS BY TYPING IN ALL CAPS!!!1)

1. Last year, I weighed about 177 +/-3 pounds. Now I weigh about 145 +/- 2 lb (Edit: actually 135 at the time of the post. Reweighed myself and that was the new weight.). I reached 145lb during late September while not fully on the diet and maintained it, except for an unknown period in late December - mid January where I went up to about 152lb, I think that implies something back home caused me to gain weight, although whether it's food or vacation loafing is hard to say.
2. I used to have consistent problems staying awake in morning classes, and large amounts of brain fog after meals. These problems have largely vanished, except when I take a meal off the diet or have had insufficient sleep for other reasons such as (see 3).
3. I, unlike wmorgan, have been food poisoned. I think I narrowed the likely causes down to either eating factory eggs from chickens without antibiotics used on them or improperly preparing chicken livers. Since then, I have replaced the factory eggs with pastured ones with cooked whites (which also happen to taste better) and replacing chicken livers with beef.
4. I feel a lot more focused on days where I have bulletproof coffee to pull me through, until the coffee wears off anyway. Note that days where I take the coffee are also days where I feel I've had insufficient sleep.
5. I took a blood test during the latter part of December, which indicates that my numbers are stellar. Now, I realize that I was off the diet by then and not adhering particularly well before, but at the very least, short term consumption of this diet wouldn't damage you more than half a month's worth of a standard diet could fix you. At most, it can heal you for more than half a month's worth of a standard diet!
6. On occasions where I deviate from the diet (social events, dashing out without breakfast, cravings for pizza), the effect is very noticeable: About 20 minutes after eating, I get steadily increasing brain fog, then get nearly knocked out for the next 15 minutes. A headache then persists for two hours after. Sometimes I wake up with headaches the next day. This is either an effect of the diet, or me simply noticing I have a gluten allergy (I haven't been tested yet). Either way, if you value gluten products, pizza and soda more than you expect to gain from this diet, it's something you should be aware of.

Notes: My meals consist of one of the following: 5 cups of steamed broccoli + 3-4tbs grassfed butter, 4 softboiled eggs / Sunny side up + Bulletproof coffee. ~2/3rds a pound of liver + 2 sunny side up eggs + 2-3tbs butter, two baked sweet potatoes + 4tbs butter. Carb cravings are stopped with a handful of berries at night when I get them (once a month). I eat only twice per day, with no substantial pangs from hunger unless I skip breakfast or I end up staying 8+ hours at school (ah, the wonderful experience of a physics undergraduate on a quarter system.) It's not hard to stick to the diet when you know you lose two hours of the day to it and feel terrible to boot.

The one weekend where I made the bulletproof ice cream was a pretty damn decadent weekend of my life. If time and the spirit of adventure are available, I'd say it's a go.

I drink a concoction loosely based on Bulletproof Coffee almost everyday and have been following a mostly Paleo Diet for over half a year now. I don't want to oversell it, but these kinds of dietary changes have been extremely valuable to me. I originally planned to run a series of about 3-5 diet experiments, but I had so much improvement on the first one I tried, I just stuck with it and made it a life-style change (although, I still make minor tweaks here and there). I made much of my data publicly available here. Let me know if you have any questions.

I've been trying to adhere to it for a year or so. My main point of departure is that I drink a lot of diet soda and beer. My results:

1. I lost five pounds in the first two months and the weight didn't come back, despite consuming slightly more calories, and a lot more calories from fat.
2. It's easy for me not to graze on simple carbohydrates, because I feel fuller. Regardless of your nutritional philosophy, most of us agree that potato chips and cookies do nothing for you.
3. I haven't gotten or given anyone food poisoning or any other indication that my food is too undercooked. Especially for beef and lamb, I strongly suspect that I could eat it raw and be OK. Similarly, but not so much, for eggs, fish, and pork. I still cook the pink out of chicken, but I'm eating much less chicken anyway.

I can say that grass-fed roast beef is hugely tastier than regular grocery store sandwich meat, and is a big boon to my low carb diet. I started out doing the 4 hour body diet in december and lost 15 or so pounds fairly fast, and then started to stagnate. I ended up cutting beans also and am now going back down again. I don't strictly follow the bulletproof diet but mine may be a data point for similar diets.