I am currently using
wget -m to mirror a remote FTP but the speed suck, what are the good alternative (command) so we can parallel to download in order to boost the speed up?
take a look at the lftp - it's quite powerful ftp client that has option for the parallel downloads:
it's available in standard debian's repository so you should have it as well in ubuntu without using 3rd party binaries or compiling it from source.
As mentioned by pQd lftp is a great tool for that and it's included in "all" distributions.
You can run it several times with