Are they unreliable? They break down unexpectedly and require a lot of maintenance? I don't think so. Furthermore, when they break the risk is spread out - a whole lot would need to go out at the same time to cause issues.

You probably meant their output is unpredictable. But even this is wrong, since weather forecasts allow for a very predictable output.

Nuclear is neither - it requires extensive maintenance (see France), and they can go out unpredictably, taking out a lot of capacity at an instant (see France).

And turbines also take a lot less space than say parking lots.