My DX100 review is finally up. It's taken 3 months to get my thoughts together, which is a shame as the DX100's performance and abilities were obvious from day one. RMAA and square wave performance will be updated too. Overall, apart from the dismal UI speed and hardware response, this is THE player.
There is no need for an external amp at all. I've not used a piece of portable gear that performs like this does. From perfect volume balance to its ability to treat any headphone almost as a straight cable, this thing sings.
1) Thanks! Will be reading your review now, with a cup of coffee.
2) I only add an amp for a slightly different flavor of sound, somewhat better separation of elements. Amp needed? Hell no.