That's actually an interesting thing to consider; is performance or features more important to you guys?
We've got some pretty awesome features that we want to add, and while some of them may inherently help with performance (such as
Persistent SEO Titles that means the system doesn't have to keep converting content titles to its SEO'd formats), some of them almost exclusively help with the actual SEO of your content (such as
Content Related Titles).
The decision of what to focus on next is up to Cosmic but I suspect he'd also be interested in hearing what you guys think we should focus on first