I said speed for a couple of reasons. 1. Todays newer bows are pretty quiet already. Yes, I know a heavier arrow will make them even more so, but I don't shoot featherweight arrows anyway, about 5.8 gpp. So the noise factor isn't as much a concern to me.
2. I would rather have a slightly greater margin of error as pertaining to distance. If I misjudge a couple of yards, I am still in the kill.