We played a one-shot Nine Worlds game last night. It was fun, but didn't quite meet my expectations. The main reasons for this were that the characters muses were not quite as good as they could have been, and that we got bogged down in the conflict rules. The muses lacked a bit due to me rushing through character generation a bit (to get through an adventure by the end of the evening) combined with the fact that they're a new idea for the players - everyone had got the idea by the end of the game, but not so much at first.
The conflicts were a problem mainly because I hadn't reminded myself how they worked (Nine Worlds was a last minute pick when one player couldn't make it). This meant that a lot of the subtleties were forgotten the first time through, or not explained well, and so on. We also went into follow-up conflicts too many times... this was just because we hadn't set stakes well, and because of a desire to (e.g.) take advantage of temporary point gains.
In any case, we still had a pretty good time, with the players starting as heroic pirates off to rescue some enslaved relatives from Saturn. Their nemesis, another pirate, tried to trap them at first and this led to a big fight between the two aetherships. Due to some bad luck, their foe got an early advantage and pushed it as far as he could, ultimately killing the PC ship captain while the other two scuttled their ship and escaped in the other. They made their way to Saturn and begun looking for the slaves.
While they did that, the player who had lost his character quickly made up a new one - a slave, hoping to escape, who was also designed to stretch (or break) the mechanics (with 6 or 7 in Metamorphosis and other similarly extreme stats).
We then played out the slave rebellion combined with rescue attempt, which succeeded and had the two pirates team up with the ex-slave (and one reunited with his sister). They went to find the other chap they were going to rescue, but by now we were running low on time.
To finish up, I had a chimera track them down, for one final conflict (with the assumption that if they won they would free the other guy and escape Saturn). This fight was more fun, as we had the mechanics down better by this point, and went back and forward a few times before they finally took the chimera down.
Conclusions: I'm a little more cautious about running this now (not less keen, but I'll be better prepared next time). Also, not well suited to a one-shot - looking back at the one I played in a few months ago, I suddenly respect Steve's ability to keep it exciting and on track even more (I can even pick a few techniques of his that I'm regretting not using last night). Running a longer game, with no rushing over character and group generation, to get muses right is pretty much required. Plus, the fact that you would get much better at the conflict mechanics (it feels to me like 2-3 sessions of play would be enough that it would be fully taken on board).