It is certainly much better. Memory usage is much reduced, but there is a slow creep upward. With Meter Bridge, XY Plotter, O'scope, and Octave Band windows running, memory started out a bit under 43MB and has gradually crept up to 111MB after an hour. Interestingly, for half that time the Toolbox windows were covered by other applications, and so not redrawing though Toolbox was running, and for that period no memory increase occurred. At the moment, there is no audio signal input, so meters aren't "moving" but memory is still ticking upward (meter windows are visible).
OS X 10.9.1, Mini with Core i7 and 16 GB RAM. Same behavior on 2009 Mini with Core Duo and 8 GB. Doesn't seem to be related to the audio interface in use, same with built-in I/O as external USB interfaces.