When it comes to equipment - specifically boatsNbikes - I tend to have a short attention span.  What I mean is that I am always looking over the horizon for the next one to try or buy.  It's not as if I can't commit, after all i have been happily married for 15 years and together with my wife more than 20, it's more that I really enjoy dating kayaks and bikes. 
    That's why I don't buy new, or almost never.  With new stuff I buy it, I try it, I get bored, I sell it, I lose money.  Call me crazy, but I hate to lose money.  With used stuff I buy it, I try it, I sell it and I break even or lose/gain a little.  SOOO much better. 
    The other reason I love used is that I don't have to cry over the first ding or scratch.  It's a sickening feeling to put a blemish on a perfect bike or kayak, but if they guy before you did it already a new boo boo is no biggie. 
    With bikes, at least, I have settled down a bit.  After owning and riding 36 different bikes and swapping steeds at least every season for ten years I know exactly what I want and what fits my size and style.  The thing is it really took until mid-life with lot's of trial and error to figure it out.  If I had done that at full retail I would be selling pencils in a can by the Art Museum - AND I wouldn't have been married for 15 years.
    It can be a challenge to find what you want on the used market but if you are vigilant and patient almost everything comes up for sale sooner or later.  The musical stylings of Ebay and Craigslist have changed the world. 
    If you have already dated around and you know which kayak or bike you want to settle down with then you might buy new.  Otherwise save your money and save the natural resources by picking up pre-loved and recycled model.

       So which is the best choice in a kayak?  You can choose between rudder, skeg or sleek minimalism.  There plastic, polymer 'glass and kevlar. Even long and short hulls and hard or soft chine. The debate goes on with fish and swede forms, but what about simple fun as a factor?
        Performance can be a slippery mistress when the powerplant is the human body.  I have been passed by folks in heavier, wider, boats and cheaper, clunkier, bikes.  Often, in fact.  I paid more but they are going faster and perhaps having just as much fun.
       Take my own experiment as an example.  On a Monday I paddled my local 5.2M loop in a narrow-long performance oriented Eddyline Falcon s-18.  Smooth, no wind, warm.  It was a 1 hour paddle, typical for that loop in faster sea kayaks.
       On Wednesday I take the same loop in similar conditions at a similar time of day at a similar effort.  This time I use a 14' plastic Prijon Calabria.  Nice boat, but shorter and wider and heavier and more stable.  The difference?  About 3 minutes.  I recognize this is not a perfect experiment, but it does show that equipment-based performance is nominal for the recreational paddler once you reach a minimum standard of equipment performance.  That is to say that the performance difference between good equipment and great equipment isn't as big as the talk-time we give it.
        Now don't get me wrong, 4 minutes an hour is HUGE if you are racing or trying out for the olympics.  Even if you are touring that could add up, but for the common man the Prijon would be as much or more fun than the Eddyline.  It costs less, is more stable and really comfy. 
       To be honest, the Eddyline WAS more fun for me.  I just like the feel of a narrower, longer boat, but my point is that it's more about FUN and what you like than arguments about miniscule performance differences because the differences are generally miniscule.
     If you are looking to buy a kayak he definitive best choice for a kayak is the one that gets you outside and that you have FUN in.  Don't overthink it.  Nothing is perfect and making a good choice will rarely be much different than making a great choice.  Just have fun.