That depends on what you're trying to achieve. Unfortunately beauty is in the eye of the beholder and that's where you'll find some difference in regards to veneers vs lumineers.
I don't place lumineers so I can't speak from experience but this is what I've heard from other doctors.
Lumineers has more minimal tooth reduction, sometimes resulting in slightly more bulky-appearing teeth and if there is heavy staining on the teeth, sometimes it may show through. The benefits of lumineers is that it does accomplish the job of creating a better smile. It just depends on how picky you are. Also, there is less tooth reduction which is nice. There may not be a need for anesthesia even.
Conventional veneers require more tooth structure removal. The benefits include creating a slightly less bulky appearance of the teeth and usually better coverage of staining if it is heavy. Drawback... more tooth structure removed and need for anesthesia.
Both have its pros and cons. There may be others as well in regards to specifically your case. Consult your dentist and discuss your options.
Also, when I say bulky. I'm talking about 0.25mm or so. For most, its probably not noticeable but as a dentist, we work in millimeters. So again, its all in the eye of the beholder.