:wave:
Are people winning any of these?
---Short answer, Yes!

opcorn:
Are they hard to win?
---It depends on the site, the number of entries, the number of prizes, how long the sweeps runs, eligibility restrictions, etc.
If you keep up reading the Winners' Circle posts, or glancing at the titles of new posts, you will see DVD and Blu-ray wins posted. Some people win often and post their wins. Many people don't post wins, especially for items they may consider small, like a DVD. I like to know who wins and the source of the win, so I appreciate all the people who post their wins.
You can also use Search to search the SA forums and see if you find posts about a win from a particular website. Often, we receive DVDs in the mail without any insert telling us where they are from. The return address isn't always helpful, so in those cases, we never know.
Some DVD sites post the names of the winners, so you can get familiar with those and check back to see if you would be more willing to enter those.
From my own experience, I have won quite a few DVDs, from both daily and one entries. I don't enter very many because I am selective about what I want to watch, but still, I have had good DVD wins. There are some DVD sites I never enter. It is my personal choice because I have never noticed a win (this doesn't necessarily mean that there are no winners), or for my own reasons, including time management.
Other people may have different observations and different criteria for making decisions on what to enter, so keep exploring, asking, and give it a try! If you keep sweeping, you will find what works best for you.