Ok,

I listen to lame mp3s on my Rio Karma. I found, that some of them are not completely gapless, but instead there apprears a slight click in the transition for some tracks. First I blamed the Karma, but just had some testing which showed the same behaviour in foobar2000.

Ok before I say much more I just upload 2 sample files demonstrating it... I cut the end and the beginning of 2 Faithless tracks (12/13) from the album No Roots.

Something wrong with my encodings? Maybe you reencode for youself and see... Vorbis is completely gapless.

here are the samples as flac and mp3

ps: mp3s are: 3.97b1 (latest rarewares) -V2 --vbr-new