They are absolutely nothing alike other than in appearance.
GPHI is very spicy, dry, woody, sweet.
GPHII is cooling, has that tea note, sweet, close to the skin.
Longevity I think GPHI beats II, likewise with sillage too. GHPII is a lot safer than I though, so compliments i'd give to II, and when to wear...II is a bit more versatile. I is more of a colder weather scent IMO.
I love I, and I really like II aswell, but the poor longevity and sillage prevents me from buying it.