I switched from a GS4 to a Moto X and I think that both are great phones, but there are some tradeoffs.
-The software on the Moto X is way superior to the GS4. It's basically stock android with the active notifications and touchless controls. These features are actually really useful, and I can't imagine going back to a phone without them. I never used to use voice commands on previous phones, but I find myself using them all the time on the Moto X. On the other hand, the GS4 had so much bloatware that I was constantly going through apps and disabling things. I didn't find any of the features they added to be too useful, and they seemed mostly gimmicky. Also, I think the Moto X runs a little smoother (probably the combination of having a much lighter skin and having fewer pixels for the screen).
-The look and feel of the Moto X is way better than the GS4. It feels a lot nicer in my hands and it's comfortable to hold with one hand, unlike the GS4. I usually don't use cases on my phones and I'm not using one for the Moto X, but I was using one for the GS4 because of how slippery the back was. The soft touch feel of the Moto X is really nice and isn't slippery at all
-The camera on the GS4 is easily better than the camera on the Moto X and it's not even close. I do give Motorola credit for the wrist twist way of launching the camera, which I use frequently, but it's really hard to get shots that come out well. It seems like every picture I take has a lot of noise and it sometimes takes a few tries to get a non-blurry shot. I always shoot in HDR mode in order to get a decent shot on the Moto X. My pictures on the GS4 were almost the quality of a real point and shoot camera,.
-The screen on the GS4 is noticeably better. I don't notice it for watching videos or playing games, but I've noticed a few times when reading text and having to make the font bigger than I had to on the GS4. In addition you have a smaller screen in general, especially with the on-screen buttons. There's a tradeoff here however, since the battery lasts longer, especially if you're playing games on your phone.