If you are in to old time run down dumpy pool rooms I would suggest a visit to Hanks on 38th and Sheridan in Wheatridge.
Its been a pool room under several names since the '60s.
Mile High Billiards is primarily 7 foot diamonds.
There are some 9 foot diamonds but the pockets are stupid tight and not fun to play on.
There is a 12 foot snooker table with a 9 foot pool cue made by Erie Martinez.
Over all Felt is the best pool room in the Denver area.
Felt sounds good. We're getting used to crappola pool rooms in our area. We like to play local shortstops etc. which are now sparse in the Central Coast of CA. We both can play and it's kind of fun finding non-champions to spar with. I vastly prefer 9' tables, diamonds with pro cut pockets are just right.