The Milestone is all of the following things: dark, grungy, smokey, loud, kinda sketchy and a fire hazard.
It is also a fantastic venue with a very respectable bar selection.
Would I take a teeny bopper there to see the latest pop phenom: No, but thats totally okay because the Milestone wouldn't book them anyway.
The Milestone is like a better version of the basement your favorite bands used to play in in high school. You can't help but feeling like you are in it with the artist. Between sets check out the thousands of stickers that cover the place.
I will warn you that the ATM looks like it was created my Macgyver (you punch your card # into a phone and get cash from the doorguy) so come with greenbacks.