I definitely feel the same way about my desktop tube amp vs the E12, but then the tube amp needs to be plugged in and cost 2x as much.
I see a music streamer II+ like yours for ~$310, but for that price I'd want USB and Optical Inputs. Though I now tread on the verge of going OT, the AudioEngine D1 looks much more like it would fit my needs/budget. Have you heard any reason to avoid that/look at something else? Wait another month for a Bifrost?
I might want to find someone willing to trade my K712 for their Annies... purely because I'd rather have the blue
I do like the E12 but with my ipod, I don't like either of my AKGs with the E12 & Ipod Combo as they sound a bit thin and hollow in the mids so that crosses them out from being portable at all for me. The Senn HD 545 on the other hand sounds perfectly fine on that combo, so I guess the HD 545 is going to be my semi-portable headphone. AKGs from my experience are very sensitive to what they are hooked up to. They seem to shine on tube amps but what is really important with AKGs is the DAC, a good DAC completely changes them.
I got mine for $200 new, I got lucky there. That is true, would be nice if it had optical. I don't know much about DACs, the HRT Music Streamer for me was a spur of the moment thing, I bought it without really doing any research, but it turns out to be a great sounding DAC and I'm happy with it. I would personally wait another month for the Bifrost. DAC upgrades have very large impacts on the sound of headphones, people often focus on headphones and amps and don't realize how important the DAC is, sometimes it's the biggest determiner of sound quality in the system.
The Annie and K712 sound a bit different from my personal experience. The blue is nice though. Some reason I like the coppery-orange of the K712 more.