Sounds like a user misconfiguration issue to me. I've never had an issue keeping a device from going to sleep when it's... actively doing something... like running services.
It occurred in both Windows and Ubuntu. In Windows “Never” wasn’t an option for Sleep (edit; I forget if it wasn’t an option or selecting it didn’t work), in Ubuntu the usual disable sleep commands didn’t work. Someone in the Ubuntu forums suggested there was a recent power management change due to EU reg and the code around it was freshly buggy. I spent a day on it before cutting my losses.
