I've run Song of Blades and Heroes at conventions/games days and the players picked up the rules and were playing independent of my help within a turn or two. Some of the key elements that players have liked include: the unique activation system, the measuring sticks for movement/ranges, the flexibility of force composition (there are a ton of creatures/humanoids to choose from), the simplicity and intuitiveness of the two stat system (quality and combat), and the relative size of forces (6-10 figures generally). The best selling point I can give though is that.....
Almost everyone I have introduced the game to has turned around and bought it afterward.
I have played larger games of about double the standard size, generally 3 player games where one person runs two warbands verses the other 2 players. What I recommend is to keep each warband independent (or break larger forces into smaller warbands) so as to not lose activation as readily.