What do people think about 1 Hour Giveaways?

I been trying to run all my giveaways as 1 hour, so that there would usually be under 500 people in the giveaway, or sometimes under 300. I like to see people have a good chance of winning.

People who are active on the site, and keep hitting their browser refresh button, will catch these fast giveaways and join them. While people who are less active on the site, will not even catch the 1 hour giveaways. So I think the 1 hour giveaways support the most active people on the site, and give something to the most active members.

I like to hear other people's opinions on the subject. What do other people here think about 1 hour giveaways?