I suppose I should start with a disclaimer: I do not play Xin (but I know how he works)
I think it depends on what you're up against, in general.
Bloodrazor does 3% max HP per hit, so building it against a tanky, beefy team means you'll end up doing more damage to them. But should you really be focusing the beefy frontliners? If you build right, you can (situation permitting). I would pair bloodrazor with an attack speed, on hit build for maximum effect, something like Bork, wit's end or maw, rageblade, black cleaver. It means you will be squishy, but should be able to stick on targets and heal fairly well. Consider frozen mallet for added stickiness.
Warrior gives decent ad and some cooldown, which is nice. If you're going to be going off-tank, it might be a good get just for some early ad before you get your first tank item. I would consider this direction a more general build, with more options to deal with how the game is going. It's not as attack speed dependent as the bloodrazor, and you can build as much damage or tankiness as needed.
However, if you're going to go tank, cinderhulk is great. Xin is a great disruption force if you can stay alive long enough. If you go tank, you can get on carries and disrupt their focus, either forcing them to attack you or try to retreat. And once the entire team collapses on you, you can knock them away, spreading them out for your team to mop up.
Of course, there is my personal favorite, the AP Xin build. This one may not win you games, but it is a good one to do for fun every once in a while.