I've been looking at various versions of Acrobat Reader, and alternatives like Foxit Reader. On any forum discussing Acrobate Reader, you can find a few comments recommending Foxit Reader instead, because it's much smaller. So I decided to try it out.
Indeed, it is fast. It loads in a few seconds on an older computer. Its rendering looks very good, in a graphics intensive file.
But it succeeded in crashing once, and hanging once, bringing down the entire PC (an old Win98 system), but otherwise very stable platform, in under 15 minutes of testing. So it doesn't give me the impression of being a mature product.
So off it goes.