meh, I hit about 400wpm without "speed reading" techniques; I mean, that's just how fast I read. If I don't really understand the material or if my short term memory isn't working well, I'll go back and re-read it.
The thing is? slowing down between words hurts comprehension, rather than helping it. The bottleneck in my system is short-term memory. The translation of letters to words to sentences to concepts is largely automatic; but if I have a pause there? that automatic process stops. If I'm talking in person with someone, and they say half a sentence, then stop and 'uhm' for a while, I completely lose the thread of conversation.
I find it pretty believable that others are twice as fast as I am at the letters on a page->concepts translation.
That bit about re-reading? that is the primary reason that I think reading would be superior, even if I could speed speech. saying "what?" is /way easier/ when you are reading than when you are listening.
(as an interesting aside, I know blind people often use text to speech software set to run, well, much faster than a normal human can talk. Apparently they start out at a normal speed and then slowly increase the speed. I've been talking for quite some time about getting me some of that gear and learning how to use it, but I have not done so yet. I suspect it would suffer from the same "difficult to repeat just the bit you want" part, but I haven't tried.)