I can't agree with your assertion that the difference is 30%-40%, but we recognize there's a difference in Cruz's favor.
The answer of course is that all things being equal, we'd be better off with Cruz.
Except in the real world, all things never are...equal. So I could smile the day after Election Day if either one were President-elect.
I believe Cruz would run the government like a conservative. I don't know how much he would accomplish.
Trump is not a textbook conservative. He has issued written documents saying, this is what I will do. I believe he will accomplish a lot more of what he says he will do. He's got good instincts and he listens.
That's reasonable, but I must quibble with a just a few little things: I'm not sure he's demonstrated that he is a good listener, and I think his instincts are reflexively liberal all too often...all too often willing to use big government to do great things. Having said that, there's little else I disagree with in your post.