FWIW I don't really recommend messing with limit-down unless it is interfering with your gaming, movie streaming, voip, etc. It is just going to make the sync process take longer and use about the same total bandwidth anyway. Usually "sprint to idle" is the best approach.
Limit-up is another matter, since that is a measure of how much you are serving blocks to other nodes. You can currently cut that down and leech if you want to. Although somewhat anti-social, it is better than not running a node at all.
Yes, I agree. Download usually isn't a concern. Nearing max upload on most consumer connections can royally screw them up their performance, so limiting that can make perfect sense.
