We played a quick battle last night - orcs against chaotics, who included a manticore and a gargoyle in their ranks. We played the "quest for the magic item" scenario, which worked well. The gargoyle got hold of the magic javelins, but the orcs were able to rout or destroy the rest of the chaotic forces, by dint of killing an exposed leader and lodging their own Tough war chief deep into the fray, where he acted as a rallying point for his troops.
These were the main observations:
1. Unrestricted reactions lead to a fast and furious game that avoids "straggling". The initiative switched a lot, as most troops were Q4 and at least half of each warband spent most of the game out of leadership range. That led to a lot of "gambling" with two or three dice, and a lot of reactions in consequence. Because we weren't stopping to measure or check line of sight, the whole of each warband was involved far more than usual, as the one-reaction-per-model limit led to a wide spread of reactions in any given turn. This largely eliminated pockets of "stragglers" and led to a much greater feel of simultaneous movement.
2. Scenario objectives and reactions interact in interesting ways. My orcs got to the first two potential magic-item sites first. As soon as the second turned out to be empty, my son was able to use a reaction to send his gargoyle flapping towards the hilltop where the item was now certain to be. In conventional SOBH, I'd have had the chance to get my orcs moving in that direction first (and would have gambled with three rolls for the closest to try to get there first. In FF, the opponent had no need to wait for a turnover, and so the gargoyle could take full advantage of his Flying ability. I rather liked that.
3. Tough leaders give a completely different leadership dynamic. In the past, my orcs tend to have been led by a standard leader, with additional Personality points going on a hero or troll. With the different personality allocation in FF, you can splash out on fancier personalities more easily. The war chief from the SOBH roster is Q3, C4, Leader, Tough, and operates in a very different way from a conventional leader. Rather than keeping him safe, it's best to "anchor" him in the heart of a melee, where his leadership ability will allow his troops to operate more effectively, both through the quality bonus and through group moves. You can be safe in the knowledge that he'll survive quite a bit of combat. Obviously, this isn't a FF rule, but with a 400-point warband, with up to 200 points to spend on personalities, it's easier to fit in both a Tough leader and a hero or wizard to provide different tactical options.
We singularly failed to test out more of the magic, as better-than-expected weather led to most of the afternoon being spent outside and a very hastily arranged game in the evening.