All the same except for the fine points of debate and semantic arguments.

New = New (hey what else?)
Uncirculated = Never hit the tables AKA new
Like New = Might have seen play but looks as good as New or Mint.
Mint = see all of the above. AKA New

They are just different words to express the same condition. Which in my personal preference is Like New. Now why is it not just New? Heck if I know, maybe it has a piece of green felt, or was once actually saw play on a table. Which is what a gaming chip is... not some pog issued from the cage/parking lot which never was intended for or used for casino play.

My vote is, No Difference, they all mean the same thing. Just as long as we do start seeing those MS-## and bogus grading 74 or 100 levels of condition, it's fine with me.

1) New
2) Used
3) Worn
Note: See description!

It's really that simple. Any attempt at a grading system makes things so complex, it is doomed to failure. Each chip is individual. One nick, two nicks, how big are the nicks? Partial HS, how much? 3/4 or 1/2 or just discolored? Stands on edge, maybe at you house... ;-) Slightly rounded, or very rounded, who's going to sell the gauges to measure degree of "roundedness". Wear? Lots, somewhat, a little, according to who and what standards?

1,2,3 and describe, that's the way to KISS.