Although this rendition of Q is not my favorite, it is a cut above some of the other versions - and this particular usage of the "imp" image actually works - just another episode saved by the presence of Data.
The full recap can be found at Memory Alpha.
Q sums this one up well while heading to engineering with Data to assist with restoring a moon to its' orbit.
Q: So...a mechanical man is to be my teacher in the humanities...As we all know by now, Data's unique "outsider" perspective on humanity (and his romantic quest to be more human) have been used to beautiful dramatic affect on countless occasions. He calls attention to our foibles and glorifies that which makes us truly special in the cosmos. It was a stroke of genius to pair a mortal Q with Data, and that genius is the only thing that saved this episode from mediocrity. The scenes preceding his eventual decision to give himself up to the Calamarain would not have been AT ALL convincing if he'd simply been sparring with Picard. How do you go from impish, self-interested loner clinging to "the closest thing [he has] in the whole universe...to a friend" for protection...to someone with at least the courage to admit that his world view is wrong (albeit in a cowardly way)?
Simple...you show Data exhibiting all of the best qualities of man in sacrificing himself to save Q. An act that creates so much cognitive dissonance in the poor formerly-omnipotent bastard that he has no choice but to ask out loud:
Q: Data risked his own life to save mine. The Calamarain almost killed him for it. Why did he do that?Why indeed. If you're not guided by any sort of moral compunction...if you have no sense of right and wrong beyond what is good for you, as Q demonstrated in the early run of the franchise...then why would charity and self-sacrifice even exist in your mind as concepts to be understood? This is why the episodes involving Q on Voyager were so disheartening. Q was developing a real character arc! He was moving from minion of the continuum to continuum dissident for his own amusement to older wiser bastard (still teaches people lessons in his own unique and self-amusing way). He taught Picard humility (Q Who) and a respect for the fabric of his own existence (Tapestry). He taught him how precarious and precious his life (and the lives of all humans) was. He even imparted for Picard a sense of wonder and curiosity that he'd forgotten (All Good Things). He was using his power for some greater purpose in shepherding humanity toward its' vast potential. And then he appeared on Voyager and jealously pursued Janeway? And his people fought a civil war? HUH????
I prefer to pretend that the whole of his arc on Voyager never happened. In my universe, Q blinked those events out of play with the flick of his finger.
The writing isn't particularly breathtaking for most of the script...a few moments of "new human" humor and Guinan getting to stab someone with a fork for fun (LOL)...but otherwise, nothing special. EXCEPT when Q is interacting with Data. And here, they got it just right, I'd say.
John de Lancie is his usual brilliant self and we get a nice bit of star power from Brent Spiner and Patrick Stewart. The rest is only OK.
The feature-level message here seems to be...the missing link to humanity is not something you can simply acquire through power and experience. What makes us human is our morality. Q might not have come all the way to the point where he earned his soul throuh hard work and sacrifice...that would have had to be a 20-hour epic miniseries, not a one-hour show...but he took the first step and in so doing confirmed the vital importance of our moral compass.