I am currently testing KTorrent 2.2 Beta 1, for the most part it works great, howerver there is a VERY ANNOYING behaviour:

I started a torrent download with currently not enough disk space avalible for all the files in it. This is not problematic since it will takes days or weeks to complete anyway and currently there is enough space for about the half of it.

Now KTorrent pops up a message saying "Disk runnung out of space" every few seconds.
This really sucks because it always steals away your attention from what you are currently doing.

I was already planning to alter the check a bit so that it only started complaining when the freespace is approaching the limit.