Got through first episode. Extremely solid acting and the setting is one of the most interesting times in history (The "Great Army" of the Danes campaign in England in 865)....Unlike Vikings which seems to be pulling from over a few centuries of history and essentially retelling legends through a semi-ficitional character (Some not even Ragnar's, like that whole coffin trick in London? Ragnar's son did that in Italy), as Agraza said, this has some more fidelity and seems to be using a smaller character to tell a story around the big players we know.
If you enjoy historical pieces which have excellent ambiance/setting quality, like GoT/Rome, give this is a go, it is really good so far and the sets/period props are allverywell done. I'd have to watch more, but if the excellent set design and props/costumes hold, this will for sure be on that level (Rome/GoT) in terms of, at least, period quality. Or at least more in line with those kinds of shows, where adherence to setting/costume seems important (Even down to them using proper armor and shields of the time) compared to shows like Tudors or White Queen where it's more of a frilly costume historical drama. (This for sure has more grit and reality to it.)
If the acting and story continue to be good, it will certainly join those two as one of my favorites. Still early to make that call, but they've certainly got the ambiance and general direction down to get there (Something The Bastard Executioner failed horribly at). Only thing that sucks is BBCA, so no nudity =-/...? (I think the BBC is cool with nudity? So unsure if there is an uncensored version or if they made it sanitized to push it to the U.S. as well, to fight for those GoT dollars.)
In any case, hopefully this does well and continues to spur on historical pieces looking to cash in on Game of Thrones making fantasy/historical dramas cool. TBE sucked, but I was at least happy people are trying earlier periods, always glad to see new period pieces. (But this stuff does make me sad thinking of Rome...It was ahead of its time, wish it came out today now =-/...would have been amazing to get the arc of at least first three seasons they had planned out, so S2 wouldn't have had to been rushed. S2 Civil War/Death of Brutus. S3 Civil War/Death of Antony). These shows always make me think of Rome, crazy to think that Vikings literally took and held land without even enough troops to be considered one legion (Probably only a few thousand), and that was considered abigarmy of this time. Yet almost a millennia earlier Rome was fielding armies not far from there of 10+ legions, well over 50k men (Or even in England 7 centuries before)...Hopefully they talk about Rome in the show, because I know the Wessex king in this war actually used Roman tactics and old Roman forts to fight off the Danes.