I'm in the same boat. I'm still using my first smart phone I've ever owned (a Motorola Droid 3). It is almost two years old, and starting to show its age. It is very slow, takes ages to open an app, won't make calls (usually), and sometimes when I go to text, it will not put the characters into the texting field. There are a more problems, but I just learn to deal with them. Plus it never gets any more updates, and I'm still rocking android 2.3.4.
My contract was up April 30th, and I was so stoked to see that that was the time that the S4 was suppose to be released. And I waited and waited to see the official release date, with most carriers confirming a date around there. And then Verizon confirmed their date.. a month later... Now I have to deal with my Droid 3 for another month while Verizon is busy loading their Bloatware and etching their logo on my S4.
But on the plus side, it gives me a month to read reviews about it and see if it is as good as everyone is making it out to be. As well, I can see what Google has in store, if they announce the Motorola X phone at I/O this month. Or perhaps an LTE NExus 4 that will work with Verizon. At this point, any phone will be a HUGE upgrade over my current one