On my everyday watch with metal links, I have enough room to slip my pinky underneath the band. However, the watch is not loose on my wrist nor does it shift locations.
On my other strap watch, it fits fairly snug but not too tight.
On my dress watch with metal links, it is a bit more firm but not too tight and does not shift location.
I would say whichever is comfortable for you. Too tight and it can become uncomfortable. Too loose and it will be moving up and down your arm all day!