I carry an XD 45 Compact, everyday, around my small farm. I also have a 5.25 Competition. There is a bit of difference in the accuracy that I get between them, as the 5.25 is much faster, more controlable, for me. The thing has better sights, longer radius, more weight, as mentioned, already. I am former military (officer and EM) and former State Prison SWaT, so I have had extensive handgun training and practice.
Is the Compact 45 a slacker? NO!
Are there advantages to longer barrel length? Yes!
Is there a point to spending the money for a Competition weapon? Yes!
It's all in what's the intended use, I believe. You'll have to answer that one. I hope this helps a lil?