Everyone else is has describes him so well, so I'll keep this short.
    
Just like to say that Jacob Brent is DEFINITELY the best Mistofelees.  
He has the grace, the style, and that little air of cuteness need to 
play this role.
    
His best bud is ultimately Rum Tum Tugger.  They're always together, 
but your can tell that  Mistofelees has little jealous fits ("The Rum 
Tum Tugger is a terrible bore")
    
Yes, he does have a thing for Victoria.  I you watch very closely 
throughout the video (especially in "Invitation to the Jellicle Ball", 
"The Ad-dressing of Cats", and "Old Deuteronomy"), you can see 
some...um... 'playfulness' between them.
    
He also loves to be in the spotlight.  Come on!  He sings/dances a 
lot in "Invitation to the Jellicle Ball", the Broadway version of 
"Mungojerrie and Rumpleteazer", "The Pekes and the Pollicles", and, 
of course, "Mr. Mistofelees".  
    
JUST A NOTE: Mistofelees looses his shoe in the middle of "The Pekes 
and the Pollicles", but it mysteriously returns right before 
Rumplescat enters.

by Pikachacha