I've got 52 plate GSX 1400, it's great for those long lazy days out with the misses, very comfortable and very easy to ride hard or slow, just put her in sixth and she pull , love it, but to be honest, my X is my weapon of choice, it goes ok, much slower but the X has more smile per mile,
Mpg is around 56 for the X
Mpg for the 1400 is around 38
Plus the 1400 eat the chain and the back tyre,

But I will say, both bikes are keepers, can't see.myself even selling them.

Check out gsx1400.org

Very friendly lot.