New
#11
High level:
Factory restore puts the computer back to exactly like it was the day you purchased it, including all the bloat-ware and foist-ware (can you tell I don't like all the junk manufacturers put into their computers?) that it came with.
Clean install installs just the operating system. No additional junk. Your computer will run faster, but it will not have some applications you may want, so you need to look at what you use and see if it's important to you or not and if it came with the computer or you added it later on.