If I want it rendered in a clean "Instapaper" view, I get that too.
If it's ephemera, it clears automatically. If I want to have it stick around, that too.
When I actually _do_ load it up, it's reading locally from disk. This is pretty much how Readability itself works, in the app versions, and it's quick even on low-powered devices such as my rather old HTC Incredible Android phone (faster than most Web pages these days, and rather more compatible as I'm now multiple revs out of date).
As for SWF and Javascript: I tend to keep both disabled by default, and for most content, neither SWF nor Javascript are generally meaningful. There's the odd site which fails utterly to render without them (it's more than a tad bit ironic that Google's own blogging platform is one of the worse offenders), but that's pretty much the minority.
But good to know.
Maybe this is a symptom of the fact that loading orders, preloading, etc isn't built into the standard, but is hacked on top?