GoudaWeapon and I were able to play a couple games at GenCon this year, with the first game (module 1, the emerald championship one) being run by the author of the module (I can't remember his name but his HoR player number was I think 3, while mine was something in the 5 digit range I think). The next day we played in module #2 with a different GM.
The player break-down was:
Myself (never played, but listened to most/all of the Inukai APs, and a few hours of other APs, including the first episode of SirGuido's, also read most of the 4th ed books and have been working on a campaign to run later this year)
GoudaWeapon (I think also listened to all the Inukai APs and had read some or all of the core book)
Friend 1 (Listened to some of the APs, and read a little bit of the core book material)
Friends 2, 3, 4 & 5 (went through a ~2 hr primer on the system that I went over for them a couple weeks before)
So as you'll note we were all quite new to it and Myself and maybe Gouda were the only ones who really knew anything about the history/background fluff. Additionally, we were there pretty much with the express purpose of learning the game/playstyle, and most of us didn't necessarily have any specific interest in long-term involvement with HoR (many of my comments below can also be extrapolated a bit to the other organized play games we were part of that weekend, including Star Wars and D&D 5E).
I thought both sessions were pretty good, though the first one we took about 5 hrs and had to skip about half or a third of the challenges involved due to time. The second one we didn't skip anything outright but we did kinda skim over the last couple sections, including basically all of the fighting, which was disappointing since our group was partly there to get a better feel for the mechanics of the game, but again this was due to time constraints in the con setting.
Both GMs did a good job, and were very friendly and helpful in explaining the system, although the second one was perhaps a little overzealous on explaining bigger/future plot points (i.e. "this area is really cool because there's some major things that happen 6 modules from now" and/or "here's some examples of really cool things that happened to my character or memorable events in the HoR world"). While those asides did something to emphasize the scope of the HoR organization, in our case they mostly took time away from our sessions where we were mostly just trying to learn the game and get a little flavor for how it can be played.
Everyone thought that the sessions did a decent job of showing off the system, although there were one or two places where it was a little unclear how we succeeded, or how a particular challenge was supposed to be a group challenge. i.e. If I know I'm not going to win the race (as a Courtier) can I just hang back and not kill myself while the three fast bushi actually compete?
The second session I think people felt a little less enthused about, for two primary reasons:
1) The main guy that we were trying to impress the whole time was kinda a living embodiment of "Rokugan has a deep and complicated history" which can be good, but for a bunch of new players mostly just meant that we were trying to impress a prick.
2) This may have been the GM, but the skill rolls felt a little more pidgeon-holed. Especially since a fair amount of the time even succeeding fantastically at a roll meant that the main guy was perhaps tolerant of us, but still not impressed.
All that being said, I'd certainly consider running them for my home group if I had access to the modules, and I'd personally be happy to play in another one if I get the opportunity. A big part of the challenge is (I think) is trying to get someone brand new to the system/setting into a very in-depth world that has been growing for many years.