The major difference is that you have one fewer panel to build, store, move, set-up and tear down. Before the '11 panel' deck was legalized, the deck had to be 44 feet long at the centerline - you had to buy 12 (13 actually) sheets of plywood (or whatever) and cut off the equivalent of almost one whole sheet and throw it away. When the 'carrier deck, lite' designs came into being, a rules change made it possible to build a deck from 11 sheets so that they became even 'lite-r' - by making the outer radius 44 feet, rather than the centerline.
Believe me when I tell you, if you don't have a dedicated garage space or shed space to store the deck (Preferably stored on its trailer) it will at some point and at certain times of the year become a major PITA for someone in the club to store and/or move back and forth to the flying site. If it's built with 2 x 4's and plywood, each section will be well over 100 lbs and the stack will be about 5' tall, 8 feel long and 4 feet wide.
We built our deck (in spring 2000) from 1/2" OSB and 2 x 2's - each section weighs about 65 lb., and the stack is about 24" tall. For the first few years, it resided in the back of my garage and I transported it in my small pickup truck (Chevy S-10). One of the club members donated a trailer and now it resides permanently on the trailer, but the trailer has to sit out in the open and we replace plastic tarps and plastic sheathing and pay a license fee every year. I CAN, if I have to, unload it and re-load it on the trailer by myself and then I'm really glad it is 11 sections, rather than 12. If I had thought about something even closer to the ground, I would have tried to use it. I can't think of any incident or flight that has ever happened where a 4" high deck would have been superior or preferable.
Finally, we spent probably a bit over $200 for our 11 sections plus 'protective ramp' - Plywood and 2 x 4's would have cost 3 times that, easily. I would be interested to know what the cost of building a deck is today - especially using the metal studs that have been described elsewhere. I know that OSB has more than doubled in price and I assume that plywood has also.