Just my two cents and it's entirely personal opinion so to the uninitiated I'd suggest trying out several free apps or the free trial versions, each app has different playback interfaces and aren't always intuitive and certain apps will dramatically colorize your music--good and bad.
For neutral sound I prefer Denon over Accudio and EQu personally, but I often like the increased soundstage that BBE provides.
Of special note, I had completely given up on Bongiovi's DPS as it crashed frequently but noticed it was re-engineered back in the spring and reloaded it onto my IPod Touch/5 and it is much improved, it still has an odd selection of profiles and minimal EQ'ing but it seems to work exceptionally well with less expensive buds, so if you're on the fence, try the free version, it's not perfect but definetly brought new life to my old SoundMagic buds.
By the way, DPS also improves the sound output to my Toyota's stock audio, new favorite for car audio too.
Edited by mechamits - 6/24/14 at 7:09pm