Favorite Cast Iron set?

I'm looking into surprising my fiance with a nice cast iron set for our 4year anniversary this July. He has one his mother bought him for his birthday in October that he loves. I've been looking online, but I'm not really sure what brands are of good quality or if they are all equally the same (the prices seem to vary drastically, especially for sets that vary from $30-1000). I would like to stay $300 or under.