Seems mozilla recognized they made a huge mistake:
"Prepare a hotfix to disable pdf.js, targeting FF18 and 19 (all platforms, release channel)":
https://bugzilla.mozilla.org/show_bug.cgi?id=839239
Unfortunately I don't think they have recognised their mistake yet. According to the bug description this hotfix was prepared a part of a contingency plan in case they need/want to disable pdf.js:
None of the subsequent comments in the bug indicate that they have actually decided to disable itWe need to prepare a hotfix for pdfjs.disabled=true, targeting FF19 (all platforms). This doesn't need to target FF19.0a1/a2. We may not end up using this hotfix, but we should prepare/test it in case we need to utilize it.
I'm beginning to get the feeling that they are just going to leave it enabled and slowly improve it in Firefox 19, 20 and 21. Hopefully by Firefox 21 we will have something similar in speed and rendering accuracy to poppler.
pdf.js render a lot of pages and keep it in RAM. Evince render only current page(s). In the case of pdf.js a big book with hundred of pages or more will be kept cached in memory in from first page to the last viewed page. So memory consumption will be huge. Anyway memory management in Firefox is already catastrophic with or without opened pdf documents.
I just opened that 907 pages document : http://www.tldp.org/LDP/abs/abs-guide.pdf it was all rendered in about one second, and switching to page 400 was done instantly. it is faster that the adobe's plugin I used at work until now, I use to consult huge pdf documents, such as Sun frames user manuals... So, I am pretty satisfied of that new feature. I suppose, however, that it is not so good if you have low bandwich, since it renders the whole document at once...
ABS has about zero pictures or other fancy things, it's all text, no?