Ok so from @MichealHampton's link ( http://www.aosabook.org/en/nginx.html#fig.nginx.arch ) I am basically going to sum it up.
The first thing to note is that Apache 2.4 also brings in (as the link says) some interesting changes, namely the event MPM: http://httpd.apache.org/docs/trunk/mod/event.html which is more of a non-blocking version of: http://httpd.apache.org/docs/trunk/mod/worker.html designed to create as little friction as possible when it comes to IO usage by devolving work to other threads leaving the main thread free to continue its work.
This of course does not overcome the fundamental problem with Apache, which is its memory and CPU usage (it is after all a generic set of tools) but it is a step in the right direction and means that Apache does not have to be blocking anymore but can be more asynchronous.
This instantly means that Nginx can of course handle a lot more than Apache even with Apache 2.4s changes, since it uses less.
The main point about Nginx when it comes to uploads is its workers abilities to be able to not be tied to a single task despite being single threaded. Using event notifications with a tight loop to process asynchronous IO allowing a single worker to be able to take multiple (maybe 1,000s) of uploads a time even on a single worker.
This is still in contrast to Apaches non-event model, and even though Apache is going the same route as Nginx slowly it is still not quite there, however, I should reiterate that Apaches ability to run "events" continually on supporting threads while keeping the main thread free is kinda kool. The one single problem is that this still creates the blocking effect where Apache says: "This connection is running, I won't drop its blocking until it is done", so its name is not really true "event-mpm" as Apache can still suffer from the scenario laid out in the link near the following lines:
It can be merely a fraction of a second to generate or retrieve this page, but it takes 10 seconds to transmit it to a client with a bandwidth of 80 kbps (10 KB/s).
Really Apaches problems with uploading depends on what you are uploading. Since my uploads are large and could reach in the GBs Apache could pose a problem, but if you were to upload images and not much else there is a high chance that the changes in Apache could work.
That's pretty much summed up.