I'm trying to use the gog.com downloader to get Sacred just now and every so often my download speed is dropping from > 200KB/s to 20KB/s and I've no idea why. If I quit, leave it for 10 seconds then reopen the program I get the old download speed back.
I had the same problem earlier when downloading freespace, so I quit and let Firefox download it. I had > 200KB/s the whole time, so I'm fairly certain the problem is with the downloader.
I would use firefox to download Sacred, but I always get the feeling it's a bit flaky about resuming downloads if something goes wrong. I tried using wget earlier, but couldn't get it to accept the URL.

Use Firefox. It downloads pretty quickly and I haven't had a problem with the downloads via Firefox.

No matter where I download my games from, they always seems to be slower downloads. It generally starts at the speed I'd expect, then go to 80kb/s. I tried a download manager once, didn't seem to speed it up any.

Yeah, that would probably be a good idea :)