I would like to buy this DLC, but before buying I would like to know if Dead Money works right.

There will always be some type of issues.

I, however, have not encountered any aside from one time when I tried to shoot through VATS and all that happened was my character held his gun at his waist and proceded to be attacked once before returning to real-time.

My main concernings are about DLC creating new bugs in main gaime.