The version is 0.4.2.54. Device is a Droid 3.
I would say the slowness has caught my attention for a while, 4 weeks maybe.? When I tap on the app's icon, it takes longer than 1 sec, most likely over 2 seconds before I see the GUI slowly displays. It is quite a difference from GMail app. I reported this on Google Voice Help Forum at google. No one says anything in response.
I don't know if this is an isolated incident or common behaviour.