Over the weekend I received my first replacement Epic 4G, and I've spent the last few days testing it out. The rampant clicks and pops during Pandora streaming are gone, and for the most part my calls are coming through clearly. I still have the issue of echoing (where I hear snippets of what I just said echoed back to me) but it's limited to one specific person who lives an a rural area, so I can't necessarily blame Sprint for that one.
I'd like to say thank you once again to Al at the Total Communications Wireless store in Atascocita for all of his help. He apologized for my replacement taking so long and even threw in a case for my trouble. Al always works to make sure I leave the store happy. This is what customer service should be.
At this point, unless I have a windfall and can afford an iPhone 4 at full retail price, it looks like the Epic 4G is going to be my phone for the remainder of my contract term. Should anything crop up good or bad I'll be sure and let you all know.