I used to play Warhammer Ancients Battles. I loved these rules. They were very flexible for different scenarios, large or small. They had excellent flavor for each army and interesting army lists to tinker with. They also supported and encouraged me to build very large armies. Here are some shots of WAB battles with the old group.
However, I started playing with a new group and wanted to encourage playing the Ancient period. The learning curve was a little too steep and I was a little too competitive with this set. When introducing a new period to new players and potential friends, it is best not to crush them on the battle field. Instead, I chose new rules so we were learning them together and this leveled the playing field. I started with Command & Colors Ancients. This game provided challenging games in a short time period. The rules were simple enough that a new player could find success in their first games and also accommodated multiplayer games. I took my singly based figures and remounted them on 2x4" bits of foamcore to be able to play.
A new player joined the group and with him came a new rule set called Sword & Spear. He started a collection of Republican Romans in 20mm. I had some 20mm Gauls left over from a previous experiment with Warmaster Ancients, so I agreed to expand them to provide and opponent for him.
This set used the same basing as C&C:A but hexes were traded for a tape measure and armies and scenarios were home made rather than proscribed. I have played 5 or 6 games with this set and found them to be enjoyable. They are a step up in complexity and give a realistic feel to what I imagine an ancients battle should look like. Not as good as WAB but at least I am getting to play!
I found Sword and Spear rules on Wargames Vault for $10 CAD. The army lists are extensive and free. They combine the game mechanics from other rule systems. For example, dice are used to determine unit activation in a similar method used in Bolt Action. Each unit has 2 stats Discipline and Combat and may have unit special equipment or abilities like pikes or steadfast. This is similar to Ganesha games core rules where Quality/Discipline determines whether a unit can be activated or not Combat determines combat ability and special rules flavor the units.
The combat system is somewhat unique and works well. The armies have a smaller figure count which will allow me to expand into other periods for less cost and painting effort. I like the effect of large bases. They make movement simpler and have a aesthetic appeal.