I've been playing it, and I've dabbled in the AEG CCG; generally I try to keep clear of CCGs though as I have the collectors gene, and random card packs combined with Ebay would end up with me breaking the bank trying to collect everything.
Short Review: I'm enjoying it, thumbs up.
A Bit more Detail: The first problem you're going to have is that in only owning a single core set, you're not going to have a vast amount of deck building options, in fact you're going to struggle to make full 40/40 decks with it. On the upside, the first cycle is going to be pumped out at the rate of one a week in starting in November, which means that they're going to be dumping 120 more cards (in triplicate) into the pool really fast, which will help out with your options. Obviously, your other choices are to get one or two more core sets, which certain customer groups balk at, but I pretty much side with FFG, as I reckon it's better to get more variety and allow the customer to scale themselves as the core sets are most 1x copies.
I mean, look at Netrunner. My third copy of that netted about 7 cards for £30, at least with the newer games they do, there's a lot less waste!
In terms of the game itself, there's a lot to like about it: -
Economy - One of the bigger problems with the L5R CCG was that a huge chunk of your deck needed to be devoted to economy, and it's really really hard to make economy cards interesting. FFG have done away with that and all clans have a similar income. Additional income is made at various decision points throughout the game. If you pass first in the Dynasty Phase, you get paid. Currency is stacked on unclaimed rings, so when those rings are next selected you get the money. So basically, if you need more cash, you make the decision to get it, but that isn't always your optimal route. If it is, great.
Permanent, ongoing board wipe forever - I'm a massive fan of board wipe mechanisms; Game of Thrones was amazing because of the Valar Morghoulis card - this game has your characters permanently and slowly fading away, so you not only have to decide what characters you want to get out, but also how long you want to keep them for by paying more resources for them. It means that serious board threats really only need to be weathered if you can't deal with them.
Reduced snowballing - in the original CCG, if you had a province broken, you were pretty much into a death spiral; you had less cards to play out, which meant that you were less likely to be able to mount a successful defence, let alone attack - so you'd likely get more provinces broken. In this version, if a card comes up in a broken province, you always get a chance to put it into play before it's lost, so while you're making decisions under a bit of pressure, they're likely not going to be all that different to the decisions you'd make anyway. The fact that incomes are now fixed for the most part means that nobody gets dicked over because they didn't draw their money cards - but of course it can all go a bit wrong still if all your characters are high cost; but that's a deck building issue.
A Game of Inches - In terms of conflicts, this game is very much a game of inches. Game of Thrones pretty much had events like "All attackers die. lol", which was often utterly horrendous and changed the dynamics of the game enormously fast; L5R makes lots of tiny adjustments with it's events and characters, so it's more of a balancing act. I've had a lot of success as Scorpion by just nudging ahead of my opponent little bit by little bit each time, depleting my hand as it's easier for the Scorpion to rebuild theirs.
Decision Points - There's a lot of decisions to make in this game. What characters to play? Should I pass first? How many cards to I want to draw and is that going to hand too much honour to my opponent? Should I defend? If so, by how much? Which ring is in play? Is this a Military of Political conflict? What are the effects of the region I'm attacking? etc. There's constant questions, and while sometimes the decisions you'll make are "blind" (such as selecting card draw), you can always make educated guesses from the state of the board.
There are a few things I like less: -
Length of play - This can be a long game. Expect your first few games to hit at least two hours. This is partially because everyone is reading the cards they have but also because of the density of the decision points. Added to that, if one player really gives up on attack and commits to defending they're setting themselves up to lose, but over a really long timescale. Generally I'm finding that it's worth allowing a province to break if you can trade for more. It's natural for people to want to protect themselves more than they should when they're learning the game, but it can lead to frustration. If it helps for reference, I've got 6 or 7 games under my belt now and we're getting down towards an hour. Once we start learning the tricks of the clans and breaking provinces is less of a "let me work this out" headache, I reckon we'll hit 45 mins.
This game is heavy for a card game - I can play a couple of games of Game of Thrones or Netrunner on the trot, no problem. By the end of one of these I'm a little bit brain-wasted. This is not a game I'll ever be doing tournaments for.
The Community - Oh dear god, the L5R community are a bunch of crazies. Like 21 pages of discussion on whether a character depicted in the art on the card is wearing their clothes the right way. Should that be tucked in on the left or the right? Perhaps we're looking at a picture of of somebodies reflection in the Mirror? It can be quite offputting, and while a lot of people are friendly, there's a lot of snobbery around L5R in terms of lore, but then people have spent about 2 decades learning the intricate history of a place that doesn't exist. FFG have of course chosen to reboot, but that's not stopping it all, and I expect any deviation from the expected in the future is going to be met with much wailing and gnashing of teeth.
Overall, I would recommend the game. The rules are pretty intuitive and easy to pick up - and generally you'll learn it fast. there are some deck building quirks I missed the first time (no more than 10 characters in your Conflict Deck is one I missed initally), and I'm really enjoying it a lot!