For me v0.9.9 has been great apart from 1 strange issue where the top layer is all perimeter as if the minimum perimeter is set to 100 (it is set to 2).
The really odd thing is that when slicing multiple stl files on the same plate 1 will be all perimeters whilst the other has only 2 perimeters so its inconsistent.
I'm running a Mac 10.6.8 with Repetier Host 0.53
PrintB.it