I was going to rate #1 & #2 the same rank, but on further playing i had to make a S+ rank PS: I rate titans heavily on their stand alone ability, all titans are nigh unkillable, but only a few have fleet/fortress killing potential & the ability to make a person crap themselves trying to deal with it. Faction bonuses are iffy in consideration, some can become hugely powerful depending and I'll try to cover some of them.
I just wanted to give my own insights after playing the different titans and how id rate them. So yah, this is more about the titans themselves for each of the different factions.