I plan on playing the reversible routing (Teton Reserve in Driggs, ID about 30 minutes from Jackson Hole, WY) this summer and will report my thoughts.
Beyond that, the only Hale Irwin design I've played is The Valley Club just outside of Sun Valley, ID. The course is a solid track. Nothing mind blowing, nothing terrible. You can see a course tour at their website, here is a link:
http://www.thevalleyclub.org/thevalleyclub/main.htmlHole 3 presents a difficult challenge off the tee. Hitting it dead straight up the fairway with a driver generally ends up being too long and in the rocks. Hitting it directly over the bunkers protecting the inside of the dogleg leaves a sliver of fairway to find. Hitting it right of the bunkers requires quite the carry and brings the o.b. right into play. Tough driving hole.
Hole 8 is supposed to be a driveable par 4, but with a pond guarding the entire front of the hole it doesn't provide a legitimate reward for the risk. The only opening to the green is a smaller strip coming in from the left side. Since I don't know anyone that can carry the ball 325 yards and then make it turn 90 degrees right once it hits the ground and rolls, this just ends up being a short par 4.
I haven't played enough Irwin courses to know any "signature" type things he does, but at the Valley Club you'll notice that most of the landing areas for drives are tightened up both with fairway bunkers and a general squeezing down of the fairway period. It reminded me of the Tournament Course at Redstone where Rees Jones had fairway bunkers placed in that 300 yard range off the tee at every hole trying to catch drives.
As a side note, Steve Wynn is a member of The Valley Club and convinced Tom Fazio to come up and design a new 9 holes that opened up last year. Fazio never does nine hole courses but was willing to because of Steve and because the plan is for him to add an additional nine before remodeling the current Irwin course.