The swf pages generated from the pdfs that we have commonly, seem to take quite a while to load in our flash viewer. So far i've blamed the slow decompression of the swf pages which just makes the viewer stop all event processing while decompressing the swf (a couple of seconds on high end machines!).
So, we are wondering if it is the slow decompression of the vector graphics and rendering them and if we could "fix" it by using the "poly2bitmap" option.
Currently we use: pdf2swf -G -j 60 -p 1 in.pdf out.swf