I've often had issues with the stability of the downloader, mostly crashing randomly or when adding new files), however the current build has proven completely useless.
I can attest to seeing errors with the endless download, pausing and resuming appears to "fix" the issue I found but instead resulted in a corrupted file.
I'm on Windows XP Pro SP3 with a wireless 3G connection so at first I thought the issues were due to it.
However the major issue I've had occurring is the chunk errors.
http://pastebin.com/K52rSkqn Please note I'd cleaned out the app data folder already suspecting it was a big part of my issues which settled down some of the crashing which seemed to be due to the garbage collection routine while adding files or hitting the clear.
1351156437 Started downloading bonus info: divine_divinity
1351156437 Worker -1 Requesting
https://api.gog.com/en/downloader2/game/divine_divinity/
Divine Divinity info fetched
1351156446 Worker -1 Requesting
https://api.gog.com/en/downloader2/extra/divine_divinity/622/
Message: The operation has timed out
Stack trace: at System.Net.HttpWebRequest.GetResponse()
at GOGCompanionApp.ConnectionManager.MakeRequest(String uri, String method, String postedData) in C:\bp\TEMP\GOG.com Companion\ConnectionManager.cs:line 192
Inner exception:
Requested URL:
https://api.gog.com/en/downloader2/extra/divine_divinity/622/
UNHANDLED ERROR!
Message: Object reference not set to an instance of an object.
Stack trace: at GOGCompanionApp.Worker.DownloadBonusInfo(WorkerTaskDownloadBonusInfo workerTask) in C:\bp\TEMP\GOG.com Companion\Worker.cs:line 746
at GOGCompanionApp.Worker.Run() in C:\bp\TEMP\GOG.com Companion\Worker.cs:line 115
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
Inner exception: