Hmmm...That is a good question, and it's kinda a tough one for me to put my finger on.
I guess, personally, a story's amount of hope depends on the genre.
Like, if you're in a genre like "Family" or "Comedy", even with a tragic ending, you have that shining ray of hope to bring it all back around. However, if you're in a genre that's like "Thriller" or "Horror", that ray of hope can be smaller, and you can be left with an uncertain future.
Now, as for tastes, I prefer endings that end with uncertainty (leaning more towards tragic). Not necessarily tragic, but you know it's not going to be really hopeful. I really enjoy those in horror, and it kinda leaves readers to give their final interpretation!