For anyone too lazy to look at the spreadsheet, basically if we joined with Com we would make up about 1/3 of their total GDP, but we would drop the average GDP by about 100 (from our perspective our average GDP would go up about 200). The only major alliances (other than Yotsuba) that would trump us would be INNAWDS (who has no leadership(and only by ABOUT 10000) and the GGU (who would be about 2.3x ComUBA's size).
edit: I think mainly Com wants us to merge because they have a total of 6 nations in Africa. We are virtually all stationed in Africa, and it would easily mean that they would go from being virtually non-existent in Africa to being a major player in the area.
edit2: Oh by the way, this is how the forums see us (go to history of africa)
The UBA - Large, militarily active, but not very active on the political forums. Its power is much less than it seems due to its high proportion of low GDP members.
edit3: In my personal opinion, I am not opposed to an alliance with Comintern. To be honest, it would probably allow anyone in the U.B.A. to grow MUCH faster than otherwise possible, because they would (hopefully) drop some aid on our smaller nations that we can't quite get dropped yet because we are still so new. Our standing as a whole would shift more from fully African alliance members to a truly worldwide alliance (with just over 1/3 being in Africa). Of course we might get taken into a war, but really it's up to Bd. I'd say have a poll.