I use Jepps because they're easier to read than NACO...at least in my opinion. Both the NACO and Jepp low enroutes are easy to read, so I don't have a problem using NACO if I have to. The approach plates are where I differentiate. If I'm shooting an approach, DP, or whatever, the LAST thing I want to is have to search for something. Jepps use big bold numbers and letters that catch your attention in-flight. Every time I look at a NACO chart, I have to scan around for a heading or altitude...it's just not written very big, so it doesn't grab your attention.
Another thing I love about the Jepps is the briefing strip. If you read it verbatim, it gives you all of your very essential information, all in one place. Also, compare the profile views of both Jepps and NACO charts. NACO shows the step-downs as a straight line to the MAP, while Jepps show actual level-offs. That helps me visualize what I'm doing much better.
Another thing that I dislike about NACO is how you have to search through the front of the little booklet to find Obstacle DP information. Jepps have that information right there on the airport diagram.
I could go on and on about why I like Jepps more than NACO, but I don't want to turn this post into a novel. And even then, I'm just biased.