I loved the song "Betcha Neva" from Cherie, it's got a very good beat.
As far as the other TAS films, this doesn't stack up for obvious reasons. There's nothing too terribly influential to the TAS mythology that occurs (unless you count Batman getting inspiration from Batwoman for the Beyond suit) and the humor's a little bland.
The mystery element was a nice approach, though you can see the big twist coming in a fair amount of time.
Penguin, Bane and Rupert Thorne are refreshing foils...though with the line of dialogue one of Kathy's bodyguards spits off it seems we can never ENTIRELY get away from referencing the Joker in some form...
Kevin, as always, does a fantastic job alongside the regulars (Zimbalist, Hastings, Costanzo) and there are great performances from TAS newcomers (Kyra Sedgwick, Hector Elizando, and even Kelly Ripa).
All in all a pretty decent watch. Definately can't be missed by HARD CORE Batman fans. But no way around it, it's ultimately a forgettable piece as opposed to "Mask of the Phantasm," "Return of the Joker," ... even "Sub Zero."
Mystery of the Batwoman - 3/5
CFE