In my country (Portugal) they do prepare my taxes and so far I can't complain. Even if something wrong happens you can file for appropriate compensation. Any payment is concluded in less than 2 weeks.
Last year the state introduces fully automated tax filling. It's beautiful. It took me 2 minutes. On the other hand, if I remember correctly its still a java app running on the browser where you have to accept an unsigned certificate and doesn't run on my mac. :/
Estonia's tax system sounds like a heaven now. It took me from start to finish 2 minutes (including software installation add 1min) and can be done on Mac, Linux and Windows, with Mobile-ID (requires special SIM card) the support extends to Android, iOS.
I'm moving to Portugal!
and it's a beautiful country on top of that! sign us up