Amsterdam has lots to offer to everyone who's a bit more open-minded in general.
Apart from the weed stuff the "grachten" (I don't have a proper translation... "canal" doesn't really do it justice) and the big parks are nice to look at and much fun especially in the summer time. The Red Light disctrict is cool at nights and there are plenty of good jazz/blues clubs etc. if you're into that. Pretty much the nightlife & weed combo does it for most people.
Wandering around the "grachten" at night while being really stoned and getting offers from both the dealers and the hookers is interesting at the very least. Doubt london could do that for me. Music sessions in the parks are way more peaceful and might appeal to more visitors though.
It might not have the Lustre London got I give you that. It probably shimmers a lot darker :)