higher gear ratio has a higher inches per reel return. Thus a 7.x.1 would bring line in faster than a 5.x.1 (this is good for example when a fish darts at you and creates slack line). On the contrary, a reel with a 5.x.1 is better for trolling or bottom fishing as it offers better cranking power. After that it comes down to your line and rod. The lower gear reels may be better paired with a heavy flipping rod for pulling the fish out of heavy cover. Beyond that, I don't really worry about the cranking ability of a reel to excessively. I suppose the cranking power and low gear set would become more important with salt water fishing.
Think about it like a truck, in 5th gear you can get up to 80mph at 5000 rpms. In 1st gear you can get to 5000 rpms, will be going much slower but creating significantly more torque. The trade off is speed vs torque.