Certainly Bantu are good at grabbing territory, and they save a ton on their cities.
Generally speaking I would say it's better to get Comm2 before Civ2 just because it is bigger boost to economy. But the third city is often crucial to reaching the Comm 2 cap (unless you have exceptional rares), so it pays to research civ2 and comm2 as closely as possible.
Or you can also get Comm 2 first, delay Civ 2, and grow your economy with Granaries/Mills, rather than more farms/wood camps in a third city. Granaries and Mills take longer to build but are better value than another farm/woodcamp.
Border pushing isn't so key for taxation as it is for grabbing mountains, forests, and rares. The middle of the map often contains the most valuable rares: diamonds, gems, papyrus, etc; Watering Hole for example. But on some maps the most valuable rares are in the corners. Great Sahara is like that.
[This message has been edited by half_lotus (edited 11-07-2003 @ 06:46 PM).]