I tried to vary the setup - but no matter the location or "choose only premium servers" option i choose to prefer, it always gets the file from Kent, UK server. I have also tried various threads count option, and there goes some interesting results. I have tried to DL the same file (soul gems differ) 10 times to see what happens - in 6 cases, the download stucked when number of threads lowered from 4 to 1 when the DL is close to finish (usually around 95 percent). When i set the number of threads to 1, it always starts at speed around 1-3 kb/s and the speed does not get up at all. Imho, the first DL connection opened is always that slow, but when i use more threads at same time, the following connections open at standard speed - and when the download is closing to finish and threads are closing, when the "slow" first thread is chosen to remain, it makes the DL to "hang on" while still showing high DL speed like the software couldnt realise there is only one thread with few kb speed left only... When "strong" fullspeed thread is selected to remain at the end of each download, it ends correctly (well this is only the opinion based on watching the behavior as i have no idea how is is coded).
This corresponds to the browser download behavior, because there, always only one thread to the server is opened - the speed varies from 1 to 3 kb/s... in browser, i have similar speeds to every premium server, free servers are bit faster (10s of kb/s) but the download is usualy timed out after few seconds. Of course it resumes again, but this is definitely not standard behavior.
As i said before, i have no troubles with downloading from anywhere else, even using various protocols like ftp or p2p. Any chance to give me the IPs of servers so i can try to track down the route?