One that appears in safari and ie (not firefox) is that the "my calendar" page puts the month view vertically centered and a big white space to the left of the day view.
The other only in safari, the "inactive" tabs (eg. my calendar if you are in my space) obscure the single pixel bottom. They are still obviously the inactive ones due to their colour - so no big useability issue, but the look is not quite as perfect.
Note also that (nearly) the same problems/fixes as apply to safari apply to Konqueror on linux.
As before - given time I will try to nut these issues out.