Of course NCAA is better than USHL. The USHL is basically a developmental league for NCAA, and many of the NCAA players already played in the USHL. NCAA players are much older than USHL (and even more so than major junior).
USHL is a great league, full of DI commits. Tends to be older than Major Junior because Major Junior is sending more players to the pros at younger ages. Just take a look at the NHL Central rankings. The vast majority of the players come from the various Major Junior CHL leagues.
CHL is older. USHL has many more 18/19 year olds leave for college. In CHL those kids stay until they age out n search of a pro contract.