For the last year or so I've been using three 163s across the front and four 153s for surrounds.

Their off-axis response is some of the best (most consistent) I've heard for a bookshelf speaker. If you play the centre speaker by itself, you'll notice that it sounds the same from any seat on your couch. Plus, reflections off the side walls (which help widen the soundstage) don't change the tonality of the speaker when they combine with the direct sound. Another advantage of consistenct off-axis response.

I set up my L/R speakers on stands and aimed them at the person on the opposite end of the couch. This really helped keep the nearby speaker from being too loud for the person on either end of the couch. I couldn't do this with my previous speakers; if they weren't pointed directly at you, they didn't sound to good (poor off-axis response).

Hope you enjoy your Infinity speakers as much as I am.