Tried a 9 iron on the course the other day...the guy I was playing with wouldn't leave me alone until I did...hit the ball well but really high flight...
They're still listed on TM's site...I'm pretty sure they're not discontinued as they are the most recent release.
I bought the rac OS2's because they were cheaper, and still are. Based on the "compare all" on TM's site, the R7XD's appear to be the replacements for the rac OS2's.
Got them beginning of the year and used them for about 20 rounds. They fly long and high so don't expect a lot of roll. I have really good feel around the green on the chips. The titanium face really makes the ball jump. I actually purchased the 4-SW set and then bought the 3,AW. and LW afterwords when I heard it was being discontinued.
I read on another website that the R7 XD's are being discontinued after one year because Taylormade is not making enough of a profit on them based on the cost of manufacturing vs. price. They will continue with the R7 CGB's. I think the they are making about $100 profit with the XD's vs. $300-$400 with the CGB's.