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Hmm, you may two points which surprise me, and which I haven't heard before. The IBIS has a great reputation in general (although clearly not in your case), and the Olympus colours are generally very well liked. The issue with the Olympus files is normally said to be that they have some noise even at base ISO in places like skies, and that they are a bit thin to work with (as opposed to fat FF files, or medium APS-C files).
Which colours didn't you like with the E-M5?
I often have an other opinion than everybody else, so it's no surprise. The IBIS is great, when it does what it does. But you don't know when it's gonna do. I'd say it's only useable at very slow shutter speeds, like 1/2-1/10 of a second with the 25 mm lens. Anything faster than that, it might just end up less sharp than if you didn't use it. Maybe I'm too steady, I don't know.
The colors look "plasticky" and I really can't put my finger on exactly what I don't like. But I think it's the lack of nuances. Noise is nothing to worry about at all and I've never cared for it, almost regardless of camera. Even the M8 was very usable to me, and THERE we can talk about nice colors.
Edit: Here's one of the less obvious examples with the 12/2. Where are all the shades of green?
1001 by Martin Hertsius, on Flickr