What is the Best MP3 Encoder program ?

I'm using Cowon JetAudio v7.0.3.3016 Plus VX Retail , and it is working well.

but is there any alternative better than it ? and what is the best ?

LAME. Don't ask 'what's best?' or people will answer LAME. Or at least those who have tried it...

I shouldn't try to know the best, may i've read an article comparing the MP3 Encoders .. etc
and for sure every one would answer from his own point of view, except someone give a prove on what he gonno say.

Agree with oliteddy, LAME is the way to go IMO. See also here and here.

I pretty much use software that uses LAME - whether in Win or Linux.
Can't say that I know it is better than other encoders, because I don't use many others

Another LAME user here, does that qualify for a pun?

*groan*

Yup, I guess that qualifies as a pun

Not sure if it still applies, but at one time, it was:

LAME for high bitrate (192k+ and VBR)
Fraunhofer for low (128k and below)

Maybe LAME has been improved to the point of being an all-bitrate champion, but initially, the tuning effort was directed towards "transparency" at higher bitrates and efficient VBR, rather than limiting the damage at non-quality bitrates.