I've had good results amping Sansa Fuze, / Clip+ from headphone out and Colorfly C3, I imagine using ELE DAC would be impressive, there's a sure increase, especially if you use the sound field or low field switch. What the amp does is give you more body and weight, smooths out any grain that might be present at higher volumes giving a more refined quality to your music. With something like the Clip+ which I was just testing you can go much louder without peaks in the upper mid range. And again the bass, mid, treble detail also black space behind your music needs a constant mention. Certainly worth it imo, it can be a fun amp using the features or a very balanced one without them.
Mine ran for 8 days (about 5 hours a day) yet still did'n't go flat before I charged it yesterday. I'm trying to narrow out any possible issue of sound quality drop after X amount of hours but still cannot detect any differences.