Nope, I sure wouldn't say that. They are basically the same product whether they are from Jepp or Gleim. I used Jepp for the PPL and it worked great. I used Gleim for all the other writtens that I did at ATP and it worked great.
I don't remember what I thought of the Jepp, but I did notice that Gleim tells you the bare BARE minimum in the begining of each chapter where they present the knowledge for you to remember. But you should already have the knowledge from other sources anyway since these are just test prep books. Both brands present the exact questions from the test bank and give you answer and a short primer preceding them. If Jeppesen's version didn't measure up to the Gleim no one would use them.
So ATP sent you Jepps? They sent me Gleims last October.
If you are doing your PPL at ATP I sure hope you take it upon yourself to do a lot of self-studying to make yourself a knowledgable pilot. I don't know what their PPL program is like but the ACPP has little-to-no ground.