I asked myself the same question in my current game (COTM 43)
I stayed in Republic all over the time, but now i want to kick some asses
I decided for Facism over Monarchy. Here are the reasons:
My opponents have a huge army (SID), so in need a huge army too! The number of allowed units in facism is superior, especially if you have more cities and metros than towns. If you have a lot of towns, communism delivers a better free unit support. However, in my game i have a lot of ics-spaced farming towns, so communism is out of order, as it would produce too much corruption in my core.
Worker efficiency is 200%, instead of 100% in a Monarchy. Well it is not an issue in my game, because i developped all the tiles already. However it may be of interest for you.
And the the last and most important reason for facism is the following:
If your opponents have a lot more culture than you, then go to Facism! In Facism, every conquered city loses 2 citizens. Add to this the draft option and people-rush-method (in Monarchy you rush with money!). With these options, you can easily get a metro down to a low number and decrase the flip-possability a lot! This is the main advantage of Facism in my eyes. Just be sure, that you have enough workers standing by, if you revolt, because your own cities will lose population too when you switch. With these workers you can easily regain the size of your core cities, and are in a perfectly designed whakking government!
