Gazoinks: I'll tell you what was confusing: Playing 3.5 (well, Pathfinder first) and then trying 2.0. Wait, high AC is bad? And what's THAC0? It didn't take that long to get used to, but it was a weird transition.
Thac0 and BAB are functionally identical. You take your Thaco, subtract their AC, and that's your target number. Add any modifiers on top of that. The only actual difference is that with BAB, you're adding up to a target number rather than subtracting down to a target number. You still want to exceed that number, and bonuses still add to the roll. Arithmetic is just hard, I guess. Pic related. It gets a lot more hate than it deserves, methinks. At least you got it, some people just see "negative is good" and their brains shut down.
Back on topic, I'll throw fistfuls of money at them as soon as they clarify the DRM situation.