Wow, this post quickly went from grit guards to choice of soap . I did some number crunching myself - based on no coupon I see available as of today, the Adam's gallon comes out to $72.40 ($20 bucks for shipping!). The Meg's Gold Class I can pickup a gallon with tax for about $13.40. If it's on sale, then basically for $10 bucks at Costco.
Michael has a point that I don't use a whole 5 gals as I mentioned before, usually half the bucket so 2.5 gallons. With the Meg's I get 51 washes with 2.5 oz per wash and 128 washes with Adam's with only 1 oz per wash. Basically, I have to use 2.5 times more Gold Class to get the same amount of washes which works out @ $13.40 * 2.5 = ~$34 bucks, half the price of Adam's car wash shampoo.
Now, I'm not trying to say one brand's necessarily better than the other, but on cost alone the Meg's GC is the winner in my eyes. Beyond cost, I really like the product and have no complaints with it - it produces a lot of suds and is crazy slick, no swirl mark problems.
Could Adam's be better, sure it can and no doubt in my mind it's a fantastic product. However, given where I live and the availability, I'm sold on Meg's Gold Class as of now unless someone literally breaks down the chemistry behind the products and shows at a microsopic level, why I should shell out the additional do-re-mi for Adam's shampoo.
Now if only my deep wheel cleaner and turbo stick could get here faster! I have to work on some Acura MDX wheels that weren't properly cleaned for a few months due to a medical reason, hopefully the turbo stick blasts away the caked on cr