I didn't even know that Sinestro Annual was going to happen. Didn't remember seeing it solicited. This was a pleasant surprise.
It's one of the couple issues this week that are less like codas for finishing/wrapping storylines and more like a total preview of the new stuff coming in June.
This takes the form of a framing device story where Sinestro and a skeleton crew of interesting folks are investigating a possible betrayal. That's set-up that leads directly into the Sinestro June storyline. But what's interesting besides the fact that the framing device story is meaty and has ramifications down the line, is that this is effectively a Secret Files & Origins issue, or a "Tales of the Corps" issue. As Sinestro muses on some of his higher circle's origins we're kind of teased about which of them might be the one who betrayed him. So we learn about Dez Trevious and Rigen Kale. We learn about New 52 Bekka's strange supergodpowers and story. Cooler still, we finally learn a bit more comprehensive backstory about Arkillo - who we've gotten to know a bit but didn't have that full of a picture of. It's a totally cool story, too.
Best of all is the appropriately Gothic as Hell backstory of Lyssa Drak. It's like a story out of 1895, akin to your Poes and Stokers and Lovecrafts and the like.