From what I can tell, being fairly new to brewing myself, this is by and large a "Coke vs Pepsi" type of thing.
By and large it seems like secondary is not needed, though there are a couple of reasons why you might want to. One is to harvest yeast from the primary. Another is if you have some additions that won't mix well with the yeast/trub bed.
I'm rethinking my shipping list for the lhbs now, based on what I have found. Instead of getting a couple carboys for secondaries, I'm thinking I may buy one for long-term fermentation and another bucket. I may avoid the carboys all together. I haven't decided yet.
Pepsi has a sweeter taste. If someone can tell the difference between two batches of the same recipe prepared with and without secondary, then their taste senses are much more powerful. The differences here much more subtle and further clouded by the beer buzz. 
