My goal with the FIIO is to have better sound quality than that which comes out of the sound card in my PC. That sound card is built into the motherboard, so I don't expect much from it. For the <$200 USD I spent for both devices, it's within the range I wanted to spend on something like this and also offers a convenience of portability with the E7. I don't think I'm at the point right now to even consider $600-$700 for a headphone amp.
I appreciate the recommendation though.