Who's used it, what are your thoughts and what kind of work have you done with it?

I've been using UnrealEd for about a year now and I've found I both hate and love the program. It is a somewhat decent editor allowing pretty easy level creation. On the flip since the editor itself is very limiting in how it lets you go about things. From the little I've used Valve's Hammer editor I've found Hammer to be a better editor in the flexibility allowed to you.

That being said it is still fun to be able to create fun maps for UT this easily.

Granted this might go better in modding editing etc but it should be more helpful if people come sniffing this way.