The "Smartkit" circuit works well enough.  It takes a few seconds to lock, but you're not going to be changing frequency all the time!  The version of that circuit that we used to use had differing filter resistors, switched in by a 4066.  This would allow lock in about 4 seconds, then would slow the filter down by 12 times to allow really low bass through, and prevent bass tilt.It added to the circuit complexity but avoided the normal compromise between lock-up time and bass response.