LAST Record Preservative: Thumbs up or thumbs down

Last #2 Record Preservative was recommended to me by an audiophile friend who uses it for his lp's. He claims it's the best treatment he's ever used. However, when I was in an analog store that sells it, the owner told me not to buy it because he found that it reduced the detail in his lp's (it's not too often someone won't sell you a product that they sell).

So my analog compatriots, if you have used Last #2 Record Preservative, did you like it or not, and why?