I was about to tear the website up for being a scam when I tried their product and it did nothing. I administered a small/reasonable amount and saw no effects whatsoever. I was upset after this, especially when I read negative reviews of the product here. Then, I administered a much larger dose than usual to see whether the amount given had anything to do with it. To my surprise, the product DOES work, but you have to administer a generous amount to your plants to see any effects. This is compensated by the fact that you get a lot more than what you ordered. In my case, I ordered 1g and there was definitely more than I gram in the bag. I did see some effects but it did not last as long or was as intense as mephedrone that I had bought in the UK on previous occasions. This is disconcerting because you have to give it to your plants more frequently to maintain the effects.
I imagine this is the case because the product is not 99.9% mephedrone (the site says it is mephedrone based), unlike UK sites before the ban. It definitely does not look similar to anything I've used in the past and its substance does not reflect that pictured on the website. It is very clumpy and sticky, not crystalline like what is depicted on their site.
Overall, it is ok and wish it would last longer. I'd advise future customers to purchase a small amount (1g) and see how you like it.