My two cents, there are differences on some issues. Other issues a party takes their stances depending on who's president like the raising debt ceiling votes of the past for example. Most Democrats voting against raising the debt ceiling during Bush Jr. while most Republicans voting for raising it. During Obama the reverse was true, Democrats voting for raising it, Republicans against.
But where they are the same is that both parties owe their hearts and souls to corporations, wall street firms, lobbyist, special interest groups, mega money donors etc. That where they get most of their tens and hundreds of millions of dollars to run their organizations and campaigns. I just went through an election where well over a billion dollars was spent by both parties on two senate elections. These two senators in my opinion were bought.
One of my biggest pet peeve is these days neither party takes the other party's proposals seriously. If one party proposes something, the other party is automatically against it regardless of the merits of it or lacking merit.Everything is party line these days solely based on which party proposed something.
So they're the same in lots of ways in much more than I mentioned while differing in other ways. Now I have come to the conclusion that both major parties always look for what is good for the party and not the nation anymore. That both fail to represent the wishes and wants of the folks back home, just their political party. So they're the same there in my book.
But this is how a non-affiliated, less to non-partisan looks at both major parties. Those who identify or affiliate with either party will have a different point of view about them.