Recently purchased one of these. It's not quite as slick as the video suggests but still works great. My two favorite things about it are that it gets the lube just where it should be, on both the inside and outside O rings on the chain which is surprisingly hard to do with just a spray can with the inside O ring. It also eliminates overspray on the bike or rear tire and you end up using a lot less lube. No clogging issues with Dupont Chain Saver but might be an issue with some lubes like chain waxes which gum up or thick greases.
- uses less lube with no wastage - ~50% less and gets more of of it on the chain
- no need to shield the bike or rear wheel with cardboard or paper towel, no overspray
- gets lube on the inside of the chain which is very hard to do with a spray can, perfectly deposits lube on the top, on both sides where it is needed
- costs $15 US plus $1.65 shipping within continental US
- takes a few uses to get proficient at using it, on first use the straw came out of the can a few times and the wire thing that goes around the can needed to be bent to fit a regular size can
- too big and bulky to take with you and too big to store in a regular tool box; you have to find someplace to store it in your garage where the straws won't get lost or misplaced
- might as well order the replacement straw kit for an extra $3 as the original straw will eventually get misplaced or broken
- shipping outside of the US is + $5 US
- you need a different Grease Ninja for every different size chain
Summary: Well worth the cost IMO if you are the kind of person who lubes their chain frequently. It becomes easier and quicker to use the more I use it. No overspray and perfect distribution of lube on the chain are it's best features.