At backend, Aspose.Words for Cloud uses Aspose.Words for .NET as codebase. In case of Aspose.Words for .NET, all the processing is done at your own server whereas in case of Aspose.Words for Cloud all the processing is done at our Cloud servers.
Our servers are really fast and processing speed is very high there but you need to send input documents and download output documents which obviously takes time (depending upon your network speed).
If your server can handle enough load and provide required performance for you then go for Aspose.Words for .NET, and if the load is too much for your server to handle or you prefer using Cloud service then go for Aspose.Words for Cloud.
As a matter of fact, Aspose.Words for .NET provides much more features than Aspose.Words for Cloud and it will take some time to implement all of those features at Cloud.
Please feel free to contact us in case you have further comments or questions.