If you don't want mp3's, or photo albums, but just want to read... then you have the perfect device. The 300 is just a good solid reader, nothing more. If you want other features than that of a reader, then the 600....900.....kindle....etc are what you need. I have an iPhone and and iPod... so music and photos are covered on them. I simply do not care to put music and photo albums on every electronic device I own.
So my answer for me is, no I would not change. But you have to decide your own answer