Everything that I do in a production fashion is running Fedora Core.
Have I had problems? Not really. I keep fairly current so I've not needed the Legacy Project. In the one case I do need it, for an RH 8.0 box, I consider the existence of the 8.0 box to be a problem (one I am actively trying to solve).
Why do I need it? Because I picked some software to use on the box that won't run on a modern FC setup. I bet on the wrong horse and I only stick with it because its a lot of effort to get off that horse. I'm working on it and I hope by the end of the month I can kill the 8.0 box, but I am not holding my breath.
While I don't need the Legacy project I know that a lot of others do. I use FC in large part because I see it as a way of being on a stable release but at the same time letting me stick my neck into the edge of open source development. Why do I want this?
I see it as a competitive advantage. I get the latest, I work with the latest, yet my stuff still works.
Years ago I use to watch Jeff and Rob run Debian on their laptops. It was a "so X work for you today?" sort of environment. I don't need this, and I don't want it.
A computer to me is about solving problems, not creating them.
The thing is every so often you bet on the wrong horse. You pick an application that doesn't upgrade. When that happens you need to be able to support the platform till you get off of it. If you are lucky this never happens, but you want that option. If you are especially smart you realize when this happens and toss out the piece which is aggravating the problem.
BTW I think MySQL Community is different for one big reason, we aren't a distribution. I listen to people compare us to Redhat, and I think they don't get it. We are software creators, not distributors. It works differently in our case. In our case Community gives us the ability to create something which is bleeding edge, something that is updated more often with features. Its a moving target and I find a moving target to be a good thing.
Why? Because the database is one place where I want every advantage I can get my hands on. The enterprise customers don't want this, they want something that is completely stable. Those who are doing web development and building software real time? Different case entirely.
Its the nature of the beast.
Yes, as Peter pointed out we have completely sucked at getting changes into the community tree. We are sitting on some great patches by Jeremy Cole that need to be merged into the community tree. I went in and merged up the 5.0 and 5.1 trees this morning so they are at least up to date with their respective upstream providers. The good news is that we have real intentions, the bad news is that we are being slow about it. One of our New Year resolutions needs to be to get better at this.