At first I had indulged myself in a holiday Olympus 40-150 R. In direct comparison with the 45-150 my Panasonic like better especially at 150mm, it is equally sharp over the entire focal length, just a great fair-weather holiday lens.
Stabilization takes in my OM-D camera, the internal stability so I can not say anything.
The tests at Photo Zone on these two lenses, I can only confirm the extent, because of the price incl. Sunshade an absolute buy recommendation, especially if one wants to use the 150mm times. Here is weakening from personal experience the Oly 40-150, and also the normal Super zoom for MFT (lt. Various tests) or for other operating systems (from our own bitter experience) provide nothing more useful from.
So anyone who trusts, sometimes to change lenses (it does not hurt, it's nothing broken ;-)), here gets the optically better combination and also saves money.