My group ran through this over a couple nights, and sort of adapted it into our current 1e campaign afterward. Initial thoughts and also I might gush a bit:
Our party consisted of an Ikoma Bard, a Mirumoto bushi (he used the Hida school for the techniques), a Kitsuki Investigator, and an Isawa shugenja. We started off with a fair bit more xp than the book suggests, as we adapted our characters directly over to the new system and we're all about rank 3 or so. We were handed 72 xp and were able to build fairly close to our already existing characters with a few things missing here and there (Where's my Ichi Miru ;_;). Creation went smoothly, and I like the simplicity and the lower numbers in the system.
We were all initially skeptical of the fancy custom dice with some people complaining that they preferred numbers, but that ended shortly after we made our initial investigation rolls to examine the crime scene. Whereas in 1e I would have combed the area on my own since I'm the only one with the Investigation skill, in this everyone was able to contribute with their various skills. This was generally met with great praise, as there are a lot of parts in previous editions where only one character can function at all, let alone be effective. Using various approaches, we were all able to contribute something, which is a wonderful thing.
This iteration of roll and keep is great and I love it. The way being trained and not trained is handled is probably the most elegant solution I've seen for an issue that's been prevalent throughout the editions. Skill dice are just better, so of course you want as many as you can get, while ring dice are useful and effective but not your best options. The addition of strife is also a great idea I think (the execution needs a bit of work, but the core idea is sound) and just the simple act of rolling dice is engaging and it blends seamlessly with the narrative. Approaches mean you're not stuck rolling awareness+courtier every time you want to ask Hida Bob for a favor, you can go for a direct approach or trick him or whatever, all using the same skill, and it all feels natural and intuitive.
Opportunity dice are a great replacement for raises. A lot of people might disagree with this, but I think raises are unhealthy and unsatisfying. You're gambling everything on what is essentially a higher probability. Once you get past a certain point in previous editions, raises mean nothing because you're always passing the TN. Likewise, you never make raises if you know you don't have a reasonable certainty of passing the roll, because as a player it's very unsatisfying to make two raises and then find out you would have passed if you didn't try to get fancy. Or the opposite problem, you get an explosion of like, 50, on a TN 15 check where you didn't make any raises, which is also incredibly unsatisfying. Opportunity dice fix all that by allowing you to add special effects or bonuses to your roll while also not forcing you to keep extra success dice unnecessarily. I love it.
Back to the game... This adventure was very intentionally mechanics-heavy, but it didn't feel like those rolls were unnecessary or out of place thanks to approaches. Asking around about the crime was also something that could involve everyone, and not just the courtier of the party, and following after the ronin was pretty easy.
The dueling mechanics are pretty interesting, though I think we should have chosen someone other than our Mirumoto bushi with the Ferocity anxiety to do it <.<. Tying the dueling system to be Iaijutsu-only in previous editions created a lot of bad gameplay and mechanical choices. 4e is especially guilty of this, where a good duelist is not a good bushi, and vice-versa. This system handles that in a way where everyone can be good at a duel, by simply using the same skills you already have. The various approaches provide a lot of flexibility in how you face off against someone.
That said, the duel between our Mirumoto and the ronin went on for several hours because both of them just sat in center stance and grunted at each other until eventually the Mirumoto decided that maybe he should attack. Then he rolled so well that he one-shot Keinosuke with a crit, in a duel to first blood. He couldn't keep fewer dice because of the Ferocity disadvantage. I love this system.
This is an issue that's been addressed by others, but why would the Crab be asking a bunch of randos to do what is apparently very important work that should be done by trustworthy Crab? We just showed up, declared one of them a murderer, and killed him. There seemed to be a rather un-crablike display of disorganization present on the Wall, imo.
We tracked down the Yasuki, the Hida and the Kaiu before the battle started (Our GM declared that searching the Yasuki storehouse took too much time to find the 4th commander we were entitled to in successfully following Keinosuke) and had our first taste of real combat when we fought the drunken Hida. Have I mentioned how much I love approaches? My Kitsuki is a pro at Kaze-do, and so I was able to wreck one of the Hida with a lot of style. Also I would like to see martial arts styles make an appearance in the game in some form (and not just open hand style), pls deliver!!! Even our shugenja wasn't scared of blowing spell slots and was able to contribute to this fight by holding one of them down with grasp of earth.
The Intrigue section didn't make a lot of sense from a flavor standpoint either. Again, this seasoned Crab vet is listening to an obviously pampered Kitsuki, a pregnant housewife Shugenja, and... Well the Ikoma and the Mirumoto were veterans of a few battles so they made sense. But STILL, the fact that my opinions held more weight than the Crab's second in command was odd to me. Though this stuff was added to showcase the varying systems so I suppose that can be forgiven, as long as that's not the norm <.<
As far as mechanics went, this wasn't very involved or interesting. It was just rolling the same thing while making different arguments every round, arbitrarily gaining points until we covered every topic. I think if there were stronger social adversaries this would be really solid, but the playtest doesn't showcase much of the mechanics of it. It mostly felt like us four PCs ganging up on this poor monk and browbeating him with words.
...I should probably stop adding in complaints about how the Crab wouldn't let literally a courtier who has never been in a mass battle in her life command a cohort of their army. But I was in charge of the Kaiu and that wasn't a great idea. Due to one very unlucky roll, the Crab army lost after taking 14 damage in one attack (down from 24, thankfully there was a wall) and a bunch of damage in a followup strike. This was unfortunate, but I think my main takeaway is don't let someone with literally no applicable combat skills fight in an army. I like the idea of command here but mass battles should have rules for rank-and-file soldiers as well. I know PCs are special fancy samurai but a big part of the world is that they're really just small fish in a big pond. Most samurai aren't going to be leading an army.
Anyway, we lost the battle, which sucked but then we ran into a 30-foot-tall oni while making our escape. This 30-foot-tall oni was capable of one-shotting any of us (and indeed, the Hida commander that was still alive got smacked down pretty early) and I'm not sure if we would have won if we weren't overleveled. I think the the army losing and not being able to give us support for this contributed to that, but the Hida got in one good hit before going down, leaving our Mirumoto and Ikoma to double-team him and finish him off. One thing I will note is that Jade Strike seemed particularly ineffective against this giant oni, as he was able to easily make his fitness roll to resist the crit that it deals.
I contributed by dealing 2 damage with the jade knife the Yasuki tried to bribe me with.
Overall, I think the system is great. There are a lot of rough spots (I'll probably make a post on a different part of the forum going into more depth) but overall I am in love with the direction this is going. The d10 roll-and-keep system has a lot of issues that were never fixed throughout any of the editions of L5R, and switching to something like this is like a man leaving the cave to see the sun for the first time.
It's difficult to go back to 1e, is all I'm saying.