You're not going to notice the difference between a 140 kg boat and a 130 kilo boat
How about 75 kg (A-cat/M18) or 107 (F16) to say a 130 to 140 kg boat ? (I-17 and FX-one are more like 140 -150 kg)
I can tell you from direct experience that you do really notice the 107 to 140 kg difference; let alone the 75 kg to 140 kg. Yep, I handled the FX-one both on sea and on land several times. Yes, it is a nice boat but don't hold your breaths; it won't break any records.
Now I will probably get accused of pushing my point here, but aren't we looking at this from completely the wrong way ?
It is not interesting to compare the I-17 and FX-one to one another. They are far to similar in every respect; and quite frankly they are both more than a little bit away from the frontline of catamaran design.
Yes the M18 is alot more advanced but for 22.000 Euro's (ex sails ?) it better be. And then still, its laminate work maybe beyond comparison and so too its mast but the BOAT design belongs more to the early 90's era than the the 00's of the new millenia. Hull shapes did progress a little bit over the last decade.
Both the Shadow and F16's are alot more interesting (sorry); both less than 14.000 Euro's when fully fitted (= including sails), a fraction slower than the M18 but also alot more likely to form world spanning classes; and lets not forget both are about 40 kg lighter than the 17 footers and more performant as well.
Personally (but I'm definately biased as a F16 owner) I don't really see the M18 justify its 8000+ Euro's higher price tag here. Especially not when you have to practically beg to be able to file the order form with their customer support department.
Clearly Sarah has chosen the M18 as her next boat, but I would have kept those 8000 Euro's in the bank for other enjoyable goods like new videogames and electronics.
Well, "I would" is not the right describtion, actually I HAVE kept it in the bank as I'm sailing F16.
Wouter