The primary battle mechanics are ok, although map variety is almost non-existent. Not having variable height on tiles is what really holds it back. Character progression is ok, although when someone randomly leaves it can really screw you over, if you've invested a lot of work in them (at the expense of others [which you have to do, as there are too many characters to level all of them]).
The game fails in that its resource management, based on a singular resource used for food, leveling, and equipment purchases, is poorly balanced. I won't spoil anything, but the game does a poor job of things midway to end. Ostensibly this is due to difficult events in the game, but the way the game teaches you to spend resources sets you up for failure later on, potentially handicapping character development.
This poor balance is seen in other parts of the game, in several scenarios, characters, and so on.
It's not that long. I finished it in 9 hours.
I liked Banner Saga enough to recommend it to people who like such games, but would have a difficult time recommending it to anyone else, and I would not say it's very great. Maybe the company's next attempt will fix some of the issues.