If you have other KEF speakers, especially a KEF center channel, and if you would be buying the IL-40s to be front speakers, I'd recommend getting more KEFs. Mixing speakers from different brands (or even from different lines by the same company) can cause tonal mismatches, which could be distracting, especially across the front soundstage. If you are intending to use the IL-40s as surrounds, this might not be as much of a problem, but could still be noticeable if you intend to listen to multi-channel music.
Take this advice for what its worth, though -- I have a feeling you are looking at the same set of IL-40s I'm interested in ($300 obo on the minneapolis craigslist?). If this keeps you from believing what I said above, you can search around for other threads on this or other forums and you'll see similar advice.