Olympus 9-18mm IQ: Better than a kit lens?

I realise that the Olympus 9-18mm has been discussed a great deal, and that a number of reviews exist (which I have mostly read). I have a qualitative question though.

How does the IQ (sharpness, contras) compare to a) the 14-42mm II kit lens and b) the good primes (e.g. 20mm/45mm)

Whilst I find the primes solid performers, the kit lens seems less consistent to me and sometimes gives a 'mushy' quality to the images. It's almost as if the images were shot at a higher ISO (I have had to check this before). I suppose I worry that the 9-18mm will also be like this partly because it has a collapsing construction.

FWIW the impression I get so far is that it will perform in general better than the kit lens and worse than the primes, but with a less uniform sharpness profile (e.g. softer-corners). Is this a sensible/accurate expectation?