There's more liquidity in the Emini S&P futures, and in my view the patterns are easier to read on ES (emini S&P futures) rather than NQ (emini Nasdaq futures).
If you are trading 1 contract then you should not notice the difference in liquidity. Take a look at the volume chart over lunchtime where you will see that the volume can get very sparse in comparison to ES.
Horses for courses, of course.