I have spent much time considering this, and trying to be honest with myself about why I prefer longer barrels. I have come to these conclusions. Long barrels are aesthetically more pieasing to my eyes. The shortest barreled double I own is 28", and it is a .410. It looks longer and much more elegant than a 28" 12 ga., the slenderness of the tubes adding a subtle "gracefulness" to it's lines, as opposed to the fat tubes on a 12.
Aesthetics aside, I have believed for most of my life that I shoot a longer barreled gun better than a short one. I have long arms so naturally grip the gun farther out the barrels than most men. This gives me added leverage in swinging. I believe this factor is not considered in most discussions of barrel length preferences, but is crucial to handling qualities in a particular gun. So, I tend to move a shorter barreled gun too quick, and stop it too quick.
That said, spending a little time with Don, and his MOI device, has been a revelation to me. He helped me see and understand that barrel length is not nearly as demanding a mistress as is where the weight in the gun is located, or distributed. I.e., a short barreled gun can actually handle more like what I feel I need than one a bit longer, if the weight is distributed farther away from the balance point. This has changed my way of thinking greatly about handling (not about looks!). I will give more consideration to that, and less to length. As a caveat though, I still find that the vast majority of longer guns suit my handling characteristics more so than shorter ones.
SRH
Like others here, this pretty well captures my thoughts. I do find that there is no prescription to barrel length and success. I have 26" barreled guns on which I wouldn't change a thing, and likewise several 29"+ that are similarly perfect to me. I do find that they all fit well, and have similar "feel", except for some purposely different (such as trap guns). Fit is all important.
