There have been others that reported/experienced freezing/delays etc with using the Spot healing brush specifically when using a Wacom tablet (I have Win7 64bit with Intous 5 tablet)
I also notice the radial filter and graduated filters will lag as well. For me the Adjustment brush seems to respond just as well as with a mouse.
In the Beta it was completely unusable and would freeze for 10-20 sec before catching up.
In the production release it improved to about a 1-3 sec delay. (The delay most noticeable when you increase the size of area been healed/changes in directions when you brush))
After upgrading the Wacom drivers I noticed the lag/delay is happening less often though it still happens.
In all cases if you use a mouse (wireless one in my case) then it works with no problems.
If I use the tablet in wireless mode it is much worse than with usb.