Yes - it's good making demos. I do this since one month and I'm sending them directly to sPlOrYgOn to don't overload filebase.
And yes - standard maps are better, but sometimes it's impossible to show some problems - then of course - if only it's possible for me - I'm downloading the map, ask You guys about pwf and after try and eventually send all to sPlOrYgOn. But this latest way only if there isn't any solution (impossible show something on standard maps). Like these doors for example or light-switches.
BTW: Last time I had some problems with demo recording. I changed tools from ClanMod to AMX. AMX doesn't have build-in some easy menu to demo recording - I was used to it from CM - so I had some trouble to switch still between CM to AMX and back. And I don't like write in console manualy record filename. But now the problem is solved - I wrote some plugin to easy demo recording and this plugin it-self is making the name of the file like playername_mapname_current-number-of-demo-on-this-map. If somebody want this for his AMX - ask me on priva. Sorry for offtopic - but maybe it can also help somebody for creating demo files.