My friend L and I played our duo characters in Blade and Soul up to the level cap (currently 45 on the NA/EU servers) and finished out the story missions. And that's as far as we're likely to go. There are several reasons, not least of which is the amazing amount of time needed to make any progress, but the last straw for me was the bot hordes that choke some of the endgame areas.
Worse, the last bit of the story forces your character into a complete 180-degree-turn in terms of motivation. No longer is everyone telling you to "remember what Master Hong would want you to do" and begging you not to give in to revenge. The teaser for the next bit of the story is basically "come to the dark side." Stuff like that can be interesting in books and movies, but when you're supposedly playing a game where you have some level of control, it's a real downer.
Despite that, L and I were still willing to look into the endgame content. We tried Mushin's Tower, which is a series of solo instances, and each of us got completely destroyed. No problem with the toughest part of the story content or the lower level dungeons, but the difficulty in the tower spiked way up. Neither of us could make it past the first couple of levels, much less get all the way to the top. Which means we needed more and better gear, since it was unlikely after 45 levels that our combat reaction skills would improve much more.
Some gear upgrades drop from various world boss monsters, and it's here that the bots first became a real problem. You'd see dozens of players just standing around the boss spawn point, doing nothing. Then the boss spawns, and they all instantly jump at it and do some big attack. Once it's down, they go back to standing around. You might see a few actual players doing the same thing, but most of them are clearly just farmer bots. We missed a couple of boss spawns and had to wait around for the next one, because the bots killed it so fast.
You also need big chunk of in-game money to upgrade. Here the main way to progress is to do daily missions in big 24-man instances. The bosses you need to kill are difficult enough to require a full team of six, and in some cases more. There weren't many bots here because the zone is large and complex, but finding a decent team is no fun. Most people you pick up through the group finder just run around following whatever their own mission log says, and if you miss one objective, tough...they're not coming back to help you finish. Worse, the spawn rates for some of the objectives are very long, so you see a lot of players camping a particular spawn, and if you happen to be a little late getting there you've got a long wait for the next one.
Then there are the daily 6-man dungeon missions, and the bots are back there with a vengeance. It's easy to use the cross-server group finder to get a group. Too easy, because almost every time you'll find that 1-2 of the people who joined are bots. They walk into the dungeon and just stand at the entrance. The game doesn't check participation, so if the rest of the group manages to make it through, the bot gets the quest rewards for free. The obvious solution would be to kick the bot from the team, but there's no such option in Blade and Soul. So you end up either taking forever to get through a dungeon with less than a full group, or going back to the group finder over and over until you manage to get a bot-free group.
Between the story disappointments, major difficulty spike in areas like Mushin's Tower, the amount of time and effort needed to grind for money and items, and the bots making it all harder, I've had it with Blade and Soul. If the developers make an effort to fix the bot problem, if they smooth out the end-game grind, and if the story is extended to some reasonable conclusion, then I might consider trying it again. Until then, I recommend staying away.