I don't think PuH belongs in this conversation, as its missing the characteristic sandalwood accords of these two. Agree that Gravel's longevity does not compare to modern synthetic powerhouses -- it's much more natural. $60 is quite a deal these days!
Here is my equation:
Gucci Envy = Gravel for Men + ginger
To be honest, I think the ginger is quite a brilliant modernizing addition. Luca Turin accurately points out that the commonly soggy effect of the ginger is skillfully avoided. Instead, it blends with the woods and herbs to create a rich balance.
Just picked up two bottles of Envy while on vacation in Orlando for a song -- perfume shop moving inventory before a move. Got an old bottle of Jicky PdT for super cheap as well.