LiLi, LiveLinuxUSB installer does a nice job of preparing a Mint xfce LiveUSB
--directly from down-loaded iso in Windows7 to LiveUSB with persistence.
Down-side of LiLi is not knowing if a chosen iso will be persistence-capable,
--and just exactly which apps will be included. Not a problem here with Mint.

Mint xfce good points:
Almost all hardware is recognized and drivers provided.
Beautiful desktop background art choices.
Touchpad can be disabled via gui.
Desktop time displayed in local time with no hardware clock utc hassle.
32-bit 'DVD' iso is only 893 Mb, so compares favorably with CD-size Knoppix

Mint xfce mixed blessings:
Firefox & LibreOffice are included; Skype, Chromium, Compiz & games are not.
Gedit is there, but hard to find at bottom of Accessories menu.
Broadcom b43 is available if one has an alternate wifi connection.
Mint is a little larger, takes longer to load, but has more apps than Knoppix.

Mint xfce difficulties encountered:
HDD partitions & secondary USBs don't mount automatically;
--the trick is sudo mkdir /media/mint; sudo chown mint:mint /media/mint.
xfce panel's added icon choices seem more restrictive than lxpanel's;
--this,too, may be just a learning difficulty.

This is a very attractive LiveUSB.