Nothing at all likable about the characters. The narrative is VERY weak, so not only do you have characters who are unlikable, you have a narrative with nothing to hang on to either. The story is really quite lacking any interesting line of consistency, and add to that the musical tropes hinge completely on anachronistic choices, which just really heightens the fact that show cleaves to an attempt at sleek, edgy production that holds zero substance in reality.
I have heard others say that if you understand Irish history it may be appreciated. Sadly, the producers missed the boat on that opportunity. It MIGHT HAVE been an chance for the producers to educate the viewers with a robust historical narrative that rang true; instead, they attempted to dazzle with sets, music, and extravagant over production with a bunch of fluff and stuff. it's merely a attempt to capitalize on the success of "Peaky Blinders" --a rip off wanna be without any of the quality attached to it.
That said, the actors appear competent. Yet, because the characters are written as greedy, backstabbing, arrogant, narcissistic, and unconscionably criminalistic, there is little compelling for viewers to care about--otherwise the cast might have had a chance to showcase the complexities of something worthy.