how would you describe the difference?

I haven't heard the MBQs but a lot of people say that they are very bright, bordering on harsh. Speakers are a very personal thing though -- someone else might prefer that brightness.

My Focals are definitely bright too. Smooth, not harsh. But bright. I have my xover set to -2, and my Concert radio treble control set to -4.

I am looking into options to remount the tweeters lower, so they dont "stand out" so much.

Sorry this is not much of a comparison, which you asked for. But I thought I'd offer my input.

-- Peter

I have some Focal 136K in the front and they sound great. Very good mids.
www.geocities.com/lac0807