They both make a good pistol, it is more of a personal preference however. The XD has a polymer frame, if thats what you are interested in, take a look at the Glocks! The difference is night and day in quality. Again, personal preference.
There are plenty of people out there that like the Bersa and the XD both and with good reason; both are fine weapons. As with any, you want to make sure they're well broken in and well maintained for proper reliability. You can go Glock as suggested, or S&W, or Sig, or Kimber; but since that's not what you asked I'll not go there. A well broken in, well maintained, and frequently verified Bersa or XD will be as effective of a tool as any of the others mentioned that have been provided equal care.
I have a XD9SC and can vouch for it's reliability. I looked at the Bersa at a gun store and if you actually hold one in your hand you can see that he quality is actually pretty impressive. They are smaller than the XD.