I can't speak for Olympus filters, but I have Panasonic multicoated protection filters on all of my lenses, and I don't get any sort of filter-induced lens flare in my images. The glass and coating are both very good, and I've never had an issue with filters stick on my lenses (though all of my lenses have plastic filter threads).
In addition to the Panasonic MC protection filters, I also have the Panasonic CPL filters, which are also excellent quality.
My 90-250mm came standard with an Olympus filter, but I replaced it with a B&W MRC, as the Olympus filter was to difficult to keep clean. In all other respects there was nothing wrong with the quality.
My thought on filters has always been that if you're going to put another glass element in front of the expensive glass you just bought, buy the best. Why spend $1000+ on a lens and try to save tens of dollars on a filter?
From my experience, that means B+W and Lee filters. There's a reason why these filters cost more than generic types, such as better glass, better materials, tighter tolerances and optical transparency.
For UV/Clear type filters, I prefer the B+W MRC Clear filter and use them on every single lens I own.