I never used that lens. So I can not really judge it. I guess it depends on what do you want to do with it. As long as the macro photography is not done with animals that need more distance to the lens, 30mm (=60mm in fuillframe terms) is not a disadvantage. Nikon has since decades a 60/2.8 Macro for fullframe FX bodies and its eeems to sell well.
I just bought a couple of weeks ago teh Olympus 60/2.8 Macro (=120mm in fullframe terms). Now this is a sensational lens. The image quality is really excellent. I actually do not Macro photography really. I just wanted to experiemnt in the future with it.
So this is a very personal choice which focal lenght you do prefer. For what do you want to use it?
I don't have any particular use in mind but I just think that with the 30mm lens the subject at 1:1 is always going to be in the shade of the camera. The Olympus 60mm macro lens sounds more reasonable. Ideally I'd like at least a 90mm lens. Of course for general photography the 30mm lens would be fine.
The longer the lens, the bigger and heavier it gets. I would not take a macro lens with me, if it would weight more than my Olympus 60/2.8 Macro. This is already at the borderline of what I am willing to carry around when I do not have a specific photo.project in mind. But thats just me. I am lazy...
yes, you get stabilisation with those cameras, which have in body stabilisation available. These are the newer Panasonic cameras of the last 2 years (GX80/GX85 etc.) and as far as I know almost all Olympus bodies.