Matt
I don't think the distinction is so great as Middleweight----->Heavweight. More like Evander Holyfield------->George Foreman. The latter can whip all ass at Cruiserweight level, and even some ass at the higher weight--if he beefs himself up--but is never going to beat the really good "Big man."
Cypress, Dornoch, Ballybunion, Merion, etc.are great Cruiserweights who can beat the best Heavyweights on their day, but not over time.
However, as to your questoin, yes, you can compare them all, jsut as Michelin can compare the best French restaurants to the best Italian , Fusion or whatever. When they give 3*** to a restaurant, you can be assured that it is "great" regardless of the national cuisine or even the ambience or even the price.
Maybe the best take on your analogy is the British phrase of "punching above your own weight." In this sense, Holyfield is the classic boxing example, and maybe Pine Valley is the classic golf course example. Either can be "beaten" over time, by the bigger hitters (Shinnecock, Carnoustie, etc. or Ali, Foreman, etc.), but each can beat anybody on their day, and virtually everybody (i.e. golfers/boxers who are not of +5 or better skill) everyday.
To put it is an historical perpsective, Rocky Marciano was arguably the best Heavyweight boxer of all time, against the people of his time, but who here thinks that he would last more than a few rounds with Lennox Lewis, today (assuming that the Rock was alive....)? Lewis "is" better (of course that depends on what you think the word "is" means......). But, who cares, and why?
Ballybunion and Carnoustie are both great. For different reasons and in different contexts. But, if you have to vote, go with the Heavyweight, everytime.