My experience with the XD subcompact wasn't that spectacular. It was a decent shooter, but I think it looks ugly. The fullsize models look good though. Maybe I'm just crazy though. They have a pretty steady following though.
I haven't shot the beretta but it feels great in my hand. Just hate the slide mounted safety. The magazines have a push down extension so your pinky has somewhere to go, but in a defensive situation you wouldn't have time to employ it. Plus, the extension leaves a small gap to pinch your finger when its pushed down. Neat idea though.
Out of the two though, I'd decide on which I could shoot better. Striker fired or DA/SA. I think DA/SA is more fun, but I shoot striker fired better. So I'd probably go with the XD.