I will say Scorpion is veritably fantastic. I've not had a chance to sample other vendor's products, but he ships quickly, his bitcoin guide is perfect (I used the coinbase -> phone bitcoin app intermediary). And, as for the product, if you are not prone to any particular sides that demand you go off (PN, etc), you will see results as long as you have discipline. For me, the motivation was the realization that every day on DNP counts (the words of another poster). I used a protein-sparing fast for the most part (reduced sweating significantly), I ran it for two weeks, took two weeks off and am about to start another cycle. I dropped from 18-19% bodyfat verified w/ 3-site caliper skinfold test, to 14-15%, a loss of roughly 20lbs after the two weeks on DNP + continuing the same diet 5 days after to dismiss any water retention common with DNP.
It's not rocket science. Get the recommended supplements list here, maintain a caloric deficit, and ideally either do a high-protein low carb/low fat diet like I did to reduce sweating (aka PSF), or do a clean carb diet if you want to sweat, but from what I see consuming fat is a mistake as there is something of an upper limit to fat oxidation rates, and you want the fat being oxidized to be the fat on your body, not consumed fat.
Taking all of those variables into account, my only other conditions were 10 20-oz water bottles per day consumed, mostly at the gym while drudging out 1-2 hours of LISS on an elliptical or a bike depending which machines were open, 2 days per week full-body weights routine, light, not to failure, just to maintain as best I could, and to keep calcium levels up I did use 2-4 scoops worth of no-carb whey (I use myprotein chocolate mint stevia, it works and it's dirt cheap, and doesn't taste too bad with just water), and aside from that some romaine lettuce, a boneless skinless chicken breast chopped up w/ montreal chicken seasoning (that seasoning could make a mammoth's ass tasty), 2x tablespoon of fat-free italian dressing, all into a ziplock bag, shook it up to coat most of it, got the rest of my protein and a little bit of extra nutritional value from the salad, some salt from the dressing helped.
Oh, and I used Morton's Lite Salt (half potassium) on the salad to help with the potassium needs of protein-sparing fasts.
While I would say what I did was absolutely viable more-so because I was 18-19% bodyfat, I'm not sure how I'd feel about doing it at a significantly lower bodyfat. DNP aside, that diet is easier when you have higher bodyfat, but when you get lower, it gets more difficult.
Oh, one more thing that was huge: the fact that you sweat a ton at 500mg/day made it even more motivating in the gym doing the cardio. I was the only guy in there dripping buckets. Your ego wins out when you look like the hardest working person in there. You'll feel like shit doing that cardio though so technically you will be, as from what I hear, most people on 500mg/day don't even go for the cardio.
Have a motivator. For me it was my 32 waist pants. I'm back in them now. Looked at them every night of those two weeks, and now they fit quite nicely. I'll probably have to get 30's after the next run, since you only want to do DNP when it's cold out. The window had to be open in 30, 40, and 50 degree nights at varying widths, but when it was in the mid-50's one night, I had to mostly open the window, so for me, that means as soon as the monthly average temps are pushing toward 50's, no DNP for me. I have 1-2 cycles left where I live before it's no DNP until November or December.
Scorpion is also extremely knowledgeable and helpful via email.
So yeah, this is a huge vouch for him, as he definitely sells a clean and potent product.