I upgraded from the Bionic to the S4 about five weeks ago, and can echo what most have said. I've had no problems with it, it is fast, and the battery lasts much longer than the Bionic did with the extended battery. I work in a low signal area, and many areas of the building have no coverage. That would suck the battery right down on the Bionic, and I was forced to use Juice Defender and/or charge it. Now on the S4 I easily get through the workday with 60%+ remaining. I was concerned about straying from Moto and their legendary radio quality so before I got the S4, my son and I compared the Bionic side by side with his S4 using the Network Signal Info app. I was surprised to find that the S4 had a notably higher signal level. At work I've noted I do have coverage more often, which is why the battery is lasting longer. If you're not interested in looking at the Moto X, then there is no reason not to get the S4.