It depends on how you define "better".
Metal has one really big disadvantage to it: metal models are heavy (which makes even small impact rather damaging), and primer doesn't adhere to metal particularly well - and the combination of those two factors makes them very prone to paint chipping. While in order to chip paint on a plastic or properly primed resin model you at least have to drop it down from a table to a hard floor, a metal model can get chipped by simply tripping over and falling onto its side on a piece of terrain. So, if you value your paint job, I'd recommend to stay away from metal regardless of any other factors.
Finecast resin however is worse than metal in just about every other regard. It has become known as "Failcast" for a reason... It is usually full of bubbles, which often ruin small detais. All long thin parts are usually warped and are hard to straighten out. And most models are literally covered in excess resin formed in vents, which makes cleaning the model up a nightmare.
So, basically, GW resin is seriously hard to get right. However, once you get through it, your paint job will last longer on it than on metal. It's up to you to decide what is more valuable to you