I've had eszopiclone (Lunesta) and I've also had zolpidem (Ambien). Was on 3mg of the Lunesta, tried taking 9mg once and was not impressed. Kind of a weird benzo-like high, but not nearly as enjoyable.
Conversely, I did not abuse the Ambien (10mg) because I was inpatient while receiving it and could not bring myself to store them up. I needed to sleep nightly. Even at just 10mg of Ambien (a strong but typical dose) I much preferred the standard dose Ambien experience to the high dose Lunesta experience (which was dealing with 9mg, three times my typical dose.) Ambien was such a pleasant calming feeling, again similar, but yet somehow distinct from benzos. I guess I just felt more of a mood lift from the Ambien.
In the spirit of the post, I didn't like eszopiclone so I have never felt the urge to procure zopiclone as it is my understanding that the only real difference is in potency, not effect. Also, to note, Lunesta is fucking expensive shit.