Well I have a open trailer that tilts, and my buddy has a deck, when just him and I go, we always take his truck and deck.
when there are more then 3 sleds we take his truck and deck, and haul my trailer behind, with the extra sleds on it.
My trailer came without a snow gaurd on the front so I built one out of aluminum checker plate for 180 bucks... (looks awesome)
in the future I am wating to buy a pickup and get a sled deck for it as, it can sometimes be a pain in the *** to haul a trailer around, while going to get groceries for a trip, or fuel ect.
The sled deck puts the sleds right up out of the path of flying rocks and debris.
however if you have a snowgaurd on your trailer, that does a pretty good job of protecting the front of the sleds.
both modes of transport I recomend covering your sleds, as salt and other crap can damage your sleds.
the only down side I see of a sled deck is the steepness of the ramp to load/unload your sleds.
My wife refuses to load or unload her sled if it is on the deck.....
You do however get use to it after you do it a couple of times.
The nice thing about the trailer is my wife can unload and load both sleds she is so confident.
Both work well... When I get my truck and sled deck, I will keep the trailer, as extra sleds will always be needed to be transported.