I've been using the Michelin Pilot Sport AS3+ for a couple years now, and they've been great. Very responsive, no tire roll in the corners and great for all season (I live in an area with only light rain and no snow). My WRX is mainly a commuter car, no track or anything like that.
That being said, are the Michelin Pilot Sport 4's the only tire worth looking at, or are there some others that might fit my needs.
I've tried Yokohama ad08, 08r, and now 09s, and Goodyear eagle f1 SuperSports on my daily. All are very grippy in the dry and offer good wet performance, but tend to wear quickly. Upside is that they're cheaper than the michelins where I live. Would recommend if you enjoy spirited driving in your day to day.
I have a Mazdaspeed 3 (stock, sadly), and I’m on my third set of Continental Extreme Contact DWS’s. If you’re open to a good all around, semi-performance tire, I definitely recommend them.