@Stefan S., breadth of configuration options, I guess. It comes with loads and loads of pre-configured xmltv sources and as such broad applicability. But honestly, it was the one I stumbled upon when looking for xmltv grabbers. There might be better options I'm simply not aware of. I've used EIT grabbers for years. Only recently entered the xmltv "world"...
@Russel Crowe: Much appreciated! Thanks.
As to your questions: You still need mono, but it is managed as a standard package depdency, i.e.: If you wanted to install the WebGrab++ package without Mono installed, DSM would complain that you'd have to install Mono first. Bu you can just intall the SynoCommunity Mono version and be done with it. The WebGrab++ package will integrate Mono automatically. No need to interfere with this aspect via ssh and command line anymore.
The only thing still requiring manual intervention, should(!) be to amend the WebGrab++.config.xml file and insert "your" channel lines from the siteini.pack directory files, which are located in the /usr/local/webgrabplus/var as well. At least this is how I used it so far. Not sure there are "fancier" use cases that are not covered yet. But if so, please let me know...