Just wondering if anyone else has tried this. Instead of running a live USB session with a persistance file, has anyone tried doing a full install of Linux Mint onto a USB stick? I got bored one night and decided to try it. I had a 32GB Sandisk flash drive laying around so I formatted it to EXT4 file system and left 2GB at the end for a swap partion. Did a normal install onto the drive from my USB live session to the Sandisk drive. Took longer than normal because it's only USB 2.0 and the write speeds are slower (I expected that). Install finished and rebooted into the new install on the Sandisk drive. Was presented with a proper GRUB menu (even showed my other drives) and booted into the session. Came up to the login screen and logged in. Desktop loaded just like it was a normal HD install and ran just like a normal HD install. The system monitor showed using only 205MB of memory and CPU was normal. Did a full update with the Mint updater which was a wopping 435 updates! Let it run, took a long time again because of the slow write speeds (about 1 hour) but finished fully updated. Installed my Nvidia drivers (ver 310) and rebooted again. System runs perfect! Behaves just like a normal install, apps load quickly, no apparent loss of speed on the menu and loading other apps, only time you notice the lag is when an app is doing any serious writing onto the drive. Graphics are fine, no issues there. I'm sure it would be much faster with a USB 3.0 drive and computer, but my desktop is older and only has USB 2.0. And oh yes.....if you plug the drive into another computer it will run, I plugged it into a laptop and it ran fine, just the grub entries don't work for the other drives. Just remember to install grub to the MBR of the USB drive, so if you leave the flash drive out you won't get a grub error message, this leaves the host computer untouched.
Have fun trying it!
Written from my USB install