I have shot the 9mma nd 45 XDs - I rented them. The 9mm rental occurred about 1.5 to 2 years ago. It was just so so to me. I guess I was unfairly trying to compare it to my Walther P99 A/S.
However - I rented the 45 ACP XD about 3 months ago. I was VERY impressed. I had zero interest in XDs before - but now my next gun will likely be a XD 45. I was amazed at the accuracy of it. And, once the trigger gets broken in (like the rental was), the trigger was very nice.
I've only shot an XD in 9mm, but I haven't looked back since getting mine 2 years ago. Not the prettiest of guns, but IMO it's comfortable to shoot for extended periods and has been super reliable for me.
My XD-9 has been reliable. I admit that I don't shoot it a lot though. I prefer DA/SA actions. The XD has some interesting features and it seems they are getting more popular all the time. They were kinda shuned at first by people on some of the froums. "It's just a Glock with bells and whistles to break".
But as time has gone on, it seems to be more and more accepted. I kinda like the grip safety and cocked indicator, and it has a trigger safety like a Glock too. It fits my hand as well as my Glock 17 does. I have no complaints about the gun and I am glad I bought one.
Up until recently, I carried a Sig P229R in .357 Sig as my duty pistol. It was recently replaced by my new Springfield XD45 and I have absolutely no regrets. First class pistol if you ask me. Lightweight, very manageable recoil, extremely robust, accurate and reliable. I now have just over 800 rounds through it with no problems at all.
I highly recommend picking one up. I got mine for $500.00 out the door. :?