The turns move quickly as each player typically has 10 or less divisions on the board at any time. The Commonwealth win by denying an Axis win. In practice, if the Allies capture Misurata, it's game over Rommel, thanks for coming. Just as TRC was an attempt to 'do Stalingrad right', TAC is an attempt to 'do Afrika Korps right'. The main mechanism for this is step reduction.
Units are mostly divisions.
There are some brigades, regiments and battalions, as well as a Rommel and an 8th Army HQ units. An HQ stacks for free. Some of the Italian units are quite good. The three step 5-6 Arete and Littorio divisions are the equal of almost anything on the Commonwealth side. Even the little infantry divisions have good staying power when stacked in defensive terrain, and are always useful for taking step losses.