On the strength of this Slate article, we acquired a copy for Christmas and finished the campaign this past weekend. We played a total of 14 sessions, including the "Prologue" game, and had a great time, especially in the earlier sessions. That's 40-50+ hours of entertainment for 4 people for $40, and no fights for several weeks over what we're playing for game night. Can't ask for a better deal than that. However, I can't wholeheartedly recommend the game without mentioning some caveats.
This is a good-looking game with solid pieces that would hold up for many, many more sessions. However, as a Legacy game, the campaign is now over, and the driving interest in playing the game (the ongoing storyline) is gone and the mechanics of the post-campaign "game" aren't exciting, so we're disposing of it. Fortunately most of the game is paper and cardboard, so it's nearly all recyclable. I'm totally down with idea of an "experiential" game that doesn't clutter up the shelves when we're done with it, but if the idea of throwing away a game gives you the willies, this one may not be for you.
You get to make permanent alterations to the board, cards, and other elements of the game. This is transgressive, and can either feel exhilarating or horrifying. Again, if drawing in permanent marker "ruins" a board game, this may not be for you.
You need to be a group that is okay with uncertainty, because as noted in pretty much every review of the game, the rules are not always clear. There were many times we felt having someone familiar with the game to act as a gamemaster would have been helpful.
Each session simultaneously takes too long and not long enough. As with most strategy games, the estimated playing time of 90-120 minutes is a gross underestimate. With setup, cleanup, keeping abreast of changes to the basic rules, and two kids at the table, we needed to set aside about 4 hours for each session. However, very few sessions saw a third in-game year. Each year is broken up into 6 turns; one of us usually won by turn 10-12, often by triggering something that gave an unexpectedly large amount of glory (victory points). I suspect this is because we made more progress on the main storyline than expected per session, partly because we tend to play games fairly cooperatively (see below). Unfortunately, this meant that long-term strategies were not worth pursuing, and even medium-term plans were ruined by unanticipated events. If your group is into making up house rules, I would be strongly tempted to time box the game so that you play a certain number of in-game years per session, possibly varying the number of years from session to session, rather than to a certain amount of glory.
There are many, many times when you're presented with an old-school "choose your own adventure" type of decision, where you might take a "cautious" path or a "bold" path, one choice will have a potentially bad effect, and it's impossible to tell which is the "right" choice from the information you have available. I'd rather the results be roughly equal, but different; for example, the "cautious" choice might result in no ill effects and give a moderate reward, while "adventurous" might cause some pain but also greater rewards. Knowing this in advance, your group might come to an agreement on how to change the risk/reward system.
It's extremely difficult to play "friendly". We like cooperative games and competitive games that don't require you to attack other players. Part of the assumption in the balancing of Seafall is that players will gang up on the player who is in the lead.
Still and all, we thoroughly enjoyed ourselves, loved the concept of the game, and hope to see others like it that learn from the experience of Seafall.