It might be cheaper to just build a level 1 SOS instead of level 4 Guild. I mean how long you going to keep it? Will you make your money back at least?
SOSs FAIL in plunder... UNLESS YOU ARE A OSF OR A EB PLAYER! In EB your spies become your main income and troops are shoved to the side where steals used to be. Always build SOSs at l2 unless exploring new lands though, else your owner doesnt gain as much stats lol. With PWs dieing out now, I recomend doing so, but upgrade to l3 when possible.
If you are planning to replace any t3 or below and always EB. If you plan to PW, use guilds. If you plan to PW, any level SOS is better just that l2 is best bang for your buck cuz you'll need higher stats for higher stat people to hit you. If you are a troop build, use guilds as you'd like the plunder in a atk even on eb better. If you are a hansel who likes to EB, SOSs all the way!