Yum-presto + University internet connection isn't a very good combo

Well, yum-presto is all cool and awesome and all, but with the lzma compression in F12 it's rather slow with rebuilding the rpms... Which means that with internet connection that can be found on many universities (up to about 10~11 MB/s when downloading from fast mirror) it's slowing the package download considerably. Here're the data from today's update.
<delta rebuild> | 79 MB 04:02
Presto reduced the update size by 65% (from 79 M to 28 M).
Package(s) data still to download: 136 M
Total 4.5 MB/s | 136 MB 00:30

Now, I wonder whether I should keep it or remove it (as half of time I use slow connection and the other half fast connection)...