Is there an objective difference in the quality of the more expensive colognes, or only a subjective difference in the smell? Is Trumper better than what Macy has, which is better than what's at Walmart? Does it last longer or anything? 

You can get a sample of Trumper colognes for the cost of shipping, along with shower gels and shaving creams. It's something like $5. Check out their website (www.trumpers.com) if you are curious.