“high performance that only nginx can provide”?
in all honesty, if you are having trouble making wordpress work correctly, than i wonder if you really have an application that requires such high performance that “only nginx can provide”, when it may actually be a lack of sufficient resources allocated to the server itself that need addressing.
I have concerns about your statement that apache is slower than nginx. From my reading, when serving static content this may be that case, however, there is an argument that when serving dynamic content, the opposite is true. essentially this means that when running php applications like wordpress cms, nginx has to pass off dynamic content processing to external handlers for execution, then wait for the content to be sent back again, only then can it relay said content to the client. Apache, accordign to the bloggs i have read about it, does all this natively “in house”. The interesting thing is, that whilst niginx has natively a lighter overhead for serving static content, Apache can also function in the same manner.
nginx also has other disadvantages when it comes to .htaccess files but then again it also has some advantages when not allowing directory overrides that apache .htaccess files provide for.
At the end of the day, which one you choose is up to you and your application.
I am no expert on these things, however, as far as i can tell, for a wordpress cms (which serves considerable dynamic content) one might actually be better off running apache over nginx!
If your website is running slowly, instead of blaming apache, perhaps you need to more closely look at your hosting provider (or vps provider). Clearly that is where your performance issues are and nginx is unlikely to really solve your issues with a wordpress cms running php dynamic content (forget caching as a wordpress solution btw, that is largely a false positive too).
finally, and i am not an nginx user, you can apparently change the nginx user in nginx.conf to anything you like.
here are some links to setting up nginx to run wordpress…i havent read through them in depth, so i hope they are of use to you.
personally, in looking at the seemingly large amount of stuffing around one has to do in order to run wordpress with nginx, i wouldnt bother! (just me)