How much flex are you looking for? The Hattori FH is quite a bit stiffer than the Gesshin Ginga. It's also a tad taller - ~39mm at the heel vs ~37mm.
In my experience, the VG10 of the Hattori is absolutely comparable to the undisclosed steel in the Gesshin Ginga.
I have to give the nod to the handle of the Hattori. You can get cocobolo or ebony as well as black linen Micarta, while the Gesshin Ginga is available only with the plain black scales.
The Gesshin Ginga also comes with a saya, that will cost you around $20-25 extra from JCK (if you want a saya, that is).
Rick