I purchased the 20GB X5L a month ago and LOVE this DAP. As a former owner of an iPod, I cannot believe how sheepishly I've followed the crowd and believed the hype. Apple has a GREAT marketing machine behind them, but I digress.
The DAP has 35 hours of BATTERY LIFE, an FM Player, line-in recording including the ability to record FM at 320kpbs AND scheduled FM recording, and even more importantly, the ability to play videos AND view pictures. (Cowon should pay me as an advertiser

)
They just relased a new beta version of their firmware which finally has opened up support for USB on the GO for Canon digital cameras (I have the s500 powershot). This basically means that I can now dump my pictures while on the road directly into my X5 without having to lug around a laptop. Awesome! ^^
All this being said, if the X5 does lack anything, it is support for browing through music via id3 tags. I personally prefer browsing my music library sorted via folder structure that I create to my liking, but it would be nice to have the option to search via Genre, Artist, Album name, etc.
I fly EWR->PER later on this week--my 35 hour battery life will surely be put to the test! Pity those folks whose iPods give way before we even hit the half-way mark.
Read the review here:
iAudiophile 10 page review
Cnet User Opinions (109 as of 8/6)
OP-I liked the Gmini as a DAP, but did not feel that it was as strong of an MP3 player as the X5. I bought my DAP primarily to listen to MP3's, which the X5 excels at (support for OGG, FLAC, etc. proves this). Additionally, while I'm not an audiophile, there are countless audiophiles who will testify to the fact that the iAudio products are superior to almost all other MP3 players out there.