Welcome Kay to TM.
I think the answer possibly lies in whether you can afford to buy new which you must be able to as it is in your consideration. Whichever route you go you won't be disappointed but will have a different experience.
Buying new will get you the opportunity to choose the spec and perhaps, if you can, get over to the factory a couple of times to see it being through built which from others who have done this say is a special experience.
We bought our 2011 4/4 Sport when it was 18 months old with 1500 miles on the clock. It has the MT&% Ford gearbox and as others have said the Madza box is a brilliant box and seems to be from new. Mine was a little stiff and clonjy until it got to about 3-400 miles and now it is wonderful so they do improve with age. There's lots of threads on here about how you can increase the power and torque on these perky Sigma engines cars. You'll have lot's of fun which ever way.
