Portable Amplifier Recommendations? (alternatives to Fiio or Headamp, etc.)
I'm looking to upgrade my mobile audio set up. I'll be running an iPhone 4/4S as my primary source (with a line out adaptor) and I use both a pair of Denon AH-D5000s and Shure SE315s (I understand these have differing demands, and hence part of my dilema). I'm having an awful lot of trouble finding some reliable posts/reviews/recommendations. It really seems like there are a lot of small, niche brands - and I feel like the limited comments are in some way incestuous.
I'm hoping to find a better portable amplifier (portable meaning self powered mainly, size isn't a huge limiting factor). I've found a lot of support for Fiio, especially the E11. But is there anything else I should be considering? Budget is flexible (nothing over $500 - and even that would be dependent on realizing some noteworthy value in a land of diminishing returns).
Does The Verge community have any experience/advice? Even a quick pointer to another place to find great info would be awesome. I'd be open to an Amp/DAC combo - but it sounds like iOS 4+ has significantly hampered the ability to take advantage external portable DACs.
Thanks ahead of time!