I was actually very excited when I heard about a new Higurashi. I have been a die hard Higurashi fan since I watch the first series and have now almost read and watched everything that even sllghtly related to Higurashi.
Considering how disappointed I was with a large proportion of Kira, I was trying my best not to get my hopes up for this OVA but upon seeing the trailer, I found it difficult not to. It looked serious, it looked exciting; Rena had her cleaver and Keiichi is armed with the bat. What's not to instantly get excited about?
In general, it was an interesting episode and longer than your typical episodes so that it is about the length of a double episode. It did however have a few flaws that with some careful thought about the plot could have been easily smoothed out.
This may be an obvious point but you should have watch series 1 and 2 before watching this.
Story: In general, the story is interesting. It deals with the 'Outbreak' (unsurprisingly) of the "virus". I will avoid going into too many details but it deals with the action from external groups and more importantly the reaction of the villagers themselves. The plot-line is very reminiscent of the original Higurashi episodes. It is dark, there is plenty of violence and you can see the connection between the club members.
Character: With a couple of exceptions, I felt this is where the episode really fell down. It was without... 'love'. Both Rena and Keiichi in particular seemed to do things that had very little emotion attached to them - unlike in the previous series, their violence seemed a little... like a spree rather than for any particular reason.
Actually Rika, despite her small part in the episode as a whole, gets me applause. Everything from her expressions and her 'Bern-esque' voice got me. I'm pretty sure there may have been some gentle underlying suggestions about the links to Umineko.
Overall: Overall I enjoyed it despite the little character flaws, it made a nice change from Kira and the 'happy-happy-love-love' Higurashi to something just that little bit darker. There seems to be doubt as to whether this is the last episode or whether there will be more. It seemed to me that the episode lent itself to a little more storytelling.