Well, first of all, it is not like ES, liquidity-wise. ES trades hundreds of thousands of contracts- YM trades maybe 30-35000.
That having been said, the liquidity is steadily growing, and the spreads narrowing- at least during the actual trading hours. If you are only trying to trade a few contracts you can get in and out O.K. and practically immediate. Outside market hours, its awful.
Personally, I prefer more liquidty.
