Brand of truck and how much truck do I need are about the only two subjects that get more heated discussions than EZ Lube. There are those of us who use them very carefully per the Dexter directions and videos and have never had a problem with them. There are people who have reported getting grease thru the seals and on to their brakes.
In my opinion, if you do it slow while continuously turning the wheel as directed, they work as designed. My guess is the problems arise from people getting in a hurry and pumping too fast and too hard.
Make your own decision.