After using a Sound Blaster E1 USB DAC for a couple of years I've always wanted to eventually get the "high end" Sound Blaster E5. I can't say I'm very knowledgeable when it comes to audio. I just got some Sennheiser HD598cs headphones and they sound great. Best headphones I've owned yet I'd like to to get a good USB DAC to get the most out of it. Other than the an upgrade to a Sound Blaster E5 from the E1, what other USB DAC's are recommended? I see the E5 going for around $180-200 yet if there is something that's cheaper and much better that would be great to know about.