Paul nailed it. Strictly a personal preference thing.
I was going to get a 26" barrel for Frankenstein, but have decided on the 30" LC. Reason, I've lots of short barrels here. I'd like to compare and contrast what's different between the long tube and the bunty li'l 21" one.
And, the guys I do an occasional snow goose shoot would love a long barrel beside them in the blind. Comments of the short barrel's blast have not been favorable or complimentary...