One big downside was that OpenResty doesn't support SPDY, due to an apparent issue when running SPDY and Lua. SPDY was an easy double digit percentage perf gain for us, so it's omission was odd.
I've had normal nginx with all the plugins (using the nginx-extras package, I think, from the ppa). No problem with Lua and SPDY at least in my use case (sending rendered HTML snapshots for anything with an HTML mime type).
I've had normal nginx with all the plugins (using the nginx-extras package, I think, from the ppa). No problem with Lua and SPDY at least in my use case (sending rendered HTML snapshots for anything with an HTML mime type).