I just wanted to show you an example of progressive rock that sounds similar to Maiden to me. You don't have to like it, but I did expect you to have some appreciation since you are such a music fan.
Yes and Maiden are really similar. I know both bands really really well! Maiden is like if Yes was Metal. That's it! If you were with me here I can sit you down and play you a bunch of stuff and you'd get it. What you heard was a crazy intro to a long song. That 5 minute bit does not sound like Maiden. Yes has like 18 albums. Its hard to just listen to 5 minutes of one song and say you hate it.
If you still want to check some out, try this video. Watch both parts though. Don't just watch one minute. Here is part 1