New stuff may be a bit better than stuff from 2006. There may be specific cases where the 2006 model was crap and it subsequently improved. However by then most of the really rubbish stuff was gone and most designers/manufacturers knew what they were doing.
People won't think you are sailing old rubbish gear if you turn up with 2005/2006 kit.
The biggest difference is that a lot of newer sails are designed for a different mast curve characteristic than the older masts which makes the older masts look like crap...
I've just got back into the sport after 8 years, i got good 2nd hand board new sails ,mast and boom and to me it's night and day. Sails and easer to use{more control} and the same with the boards.
I hooked again sailing every day now as long as there is wind