I also use the Jena Labs 3D-X. There is a noticable positive difference in playback of CD's and DVD's IMHO.
The only issue with this is the liquid will get "gunked up" in the dispenser bottle tip w/ the cap on after about 30 days or so. You have to clean it out regularly. Also, it is a bit time consuming as you apply the liquid, let it dry for 30 seconds to a haze, then wipe it off.
I do not use a large microfiber cloth instead of the supplied wiper pads. This just makes the application process easier and faster.
I have treated about 800 CD's and DVD's and only used about 1/3 of the 4 oz. bottle content. I expect you could treat about 2000-2400 discs for one 4 oz. bottle.
NB