Do you achieve better results from marinating if you poke holes in the meat beforehand?
ChefSteps inject their cuts of meat with their 'brine', a marinade of salty water, liquid smoke, etc., before putting the entire thing in that brine to speed up the process (6-7 days down to 1-2 days)

https://youtu.be/_yTLjYRDDwI?t=51s (at 51s Ben talks about the brine for a pork shoulder, and speeding it up by injecting it. They have other videos for beef, and chicken, and frequently advocate injecting brine/marinade into their meats.)

This is effectively the same as poking holes in the meat and letting the marinade seep in more effectively.

It would depend on the size of the holes you're creating, if you're jacquarding the meat the holes will be larger than a needle.

Benefits: speed up marinating, more effective marinating.

Drawbacks: Depending on hole size, you could ruin presentation and texture. Depending on the marinade, you could be affecting the colour of the meat, too.