There are no cons to the P99 - as long as U get teh A/S - seriously. You told me that you read most of the Walther forum section here on the site. Go here too, if U haven't already... http://www.waltherforums.com/vb/
The P99's trigger is fantastic. It smooths up after about 500 shots and just gets better. If U search other forums as well - you'll see all the positive comments. Guns been around since the 90s, so its also a tested design.
I've rented a few XDs. I will admit to being impressed with the 45 XD. But in 9mm, I didn't much care for it. I actually discovered the P99 and a few other guns thru renting them.