I was a bit skeptical about this at first but it was on sale at Costco so I figured I would give it a try. I know they always have good quality product and the best price - and now this product has a lot of good reviews. I couldn't find the Unger Rinse 'n' Go anywhere else. I've used a more expensive version at home in the past...but replacing the resin was a pain in the *** and expensive. This one really is much easier to use and gave me the same spot-free results. The product I had before required an engineering degree to assemble, it was ridiculous. This Rinse 'n' Go really was ready to go right out of the box. The resin was already inside. I played around with it anyway - the resin is in a bag so it's really easy to replace rather than dealing with loose resin. I didn't use it to wash the dirt from my car because I didn't want to waste the resin so I washed it like I normally do but then used this for the final rinse. That's what this system is made for - I rinsed the car with this and just let it dry. The results were great - I didn't have any spots, not even on the glass. So, I'll tell you guys, in my opinion, it you want a spotless car without having to spend all that time towel drying it, this is for you. I just wish it had a bypass for regular water if you don't want to use the resin. I just connected it when I was done washing the car as a workaround.