It's certainly worth it, but you're quite right that mileage will vary. Blood Money just happens to be one of the few games I feel an itch to play anytime they get mentioned - even now I'm resisting the temptation to start another run through, even though the missions hold no more secrets... This new Hitman cannot come soon enough!

I think it was the sadistic voyiurism of the games that made me keep replaying them. In the hotel levels, you could mess around with jumping over balconies, breaking into other rooms, leaving corpses in random locations, setting of fire alarms and generally causing mayhem, while nobody suspected you.
In Hitman 2, it had these hilarious cheats that were almost as much fun to play with as the ordinary game. One of them gave you every single collectable item in the game in your inventory, which was hilarious when you have to go through an airport scanner, and you just start dropping all this crap, knives, bottles, golf clubs, suitcases, shotguns, M60s, explosives, out of your tiny pockets like you're Doctor Who.
One of my favourites was that Indonesian building with the scanners. I broke into a locker room that was full of firemen in masks and suits, I murdered one with an axe, causing the others to flee. But because I stole his uniform and ran out to the lobby, nobody knew who I was. One of the firemen ran to a security guard and started pointing at me, but he wouldn't believe him. All the firemen started going back to their room, and the one who tried to grass on me looked so agitated, because he alone knew who was, and he knew he was going to die for trying to get me killed.
Little stuff like that, it's just so much fun how the games will react to your weird ass tangents.