I switched to radarr and I never looked back. Although I hate having mono installed in my server, at least I can manually perform searches to check if it works until I was satisfied that the "Monitoring" feature actually works. And I find the UI much more understandable too.
I also use sonarr, which is also pretty satisfying for me. Although SickChill looks much better and more feature complete; I will look into it when (if?) I manage to get back home.
Sonarr 3 isn't technically stable, but I've been running it for more than a year now and didn't have any problems worth mentioning.
Radarr, Lidarr and some others are all built off of Sonarr.
Do they basically automatically download the newest pirate movies using BitTorrent protocol? Or there is more?