Read the other reviews if you want a more thorough explanation of everything, I'll just keep this short and sweet.
Story:
This OVA sets up a really cool apocalypse type setting. The characters do make some pretty reckless/insane choices, but it's entertaining and kinda needed for the story, so I guess that's okay. The story was good, but it really needs to continue on longer. If they make more after this OVA, then everything about it will be more awesome, but right now it gets you excited and wanting more, and then it stops.
Art/Sound:
The art and sound were fine, and stayed familiar to most of the rest of Higurashi stuff.
Characters:
They are the same characters that you like/love. Sometimes Keiichi and Rena do act unrealistically reckless and commit some pretty emotionless violence toward other people, but it's fun to watch and you'll still probably like it.
Overall Enjoyment:
It's definitely worth watching if you've seen and liked other Higurashi. They better make more because the ending of this sets it up to be able to have so much more!