I've published several books with them (I absolutely love working with them), and in my opinion the editing is very much on the light side. My last edit was to convert all my dash-dashes to an em dash and add a couple of missing commas, maybe a homonym typo. That's it! Ain't no way in hell I'm that thorough. I know I'm not though the editor's notes raved about how clean my MS was. **scratches head** I've found typos post release in my books, mostly stuff caused by track changes obscuring stuff like missing spaces or commas instead of periods, that sort of thing. Nothing major though, at least not for me.
As to royalties, never had a lick of a problem over the past year. The supporting data and $$ is distributed very quickly after each quarter end and is easy to follow and understand.
Response time is lightning fast. They've also just hired a marketing manager so we're hoping for a little more structure post-release to help with sales. I was pleased that they advertised my books a couple of times on the web.
Now something new they are undertaking that REALLY has me curious is "Evernight Teen", the new line they are launching January 2013. There will be a different website for it, but beyond that, we haven't heard too much. They are taking submissions already. They want older, darker teen (upper YA / new adult) material, not surprisingly.