Disclaimer I'm not a critical type of viewer. I find I enjoy things on some level (be it story , or effects , or , more commonly, simple escapism to avoid other stuff I should be doing) more than most people who post on these boards. So take my opinion with a grain of salt
I just watched the first two episodes. I have NOT read the books or previews so basically I knew nothing about it before going in.
I'll start with my cons so far: there are three story lines going on, I kept expecting them to intersect in the episode, but nope, they are distinct ( so far anyway) and I found that a bit jarring until I realized it was going to be a slow burn to the intersection. There are a lot of characters in the first episode, combine that with the similar muted color tones of clothing and such and I admit the first episode I had no idea who was who between scenes ( i.e. If someone was in scene 1 and then again scene 4 , I didn't recognize it as the same person from scene 1). But that aspect got better for me by the second episode as by then I was accepting of the three separate stories as well as by the second episode some focus shifted to highlight who the main characters are ( I'm trying not to spoil).
Normally with new shows you have a character that acts as the audience eyes who gets introduced to stuff, but you don't really get that here , this goes back to three story lines, but I kept looking for 'that character' in the first ten minutes and I just didn't get that....that isn't a bad thing just my expectation was otherwise so it took a moment and so I don't think I actually 'got' the show , it's pacing, it's characters, it's story lines, until a bit in to the second episode.
Pros: for a tv show it has nice effects and scenes and such. Its going for a gritty realistic feel and heavily on lore ( which is a con, but at the same time I'm listing it as a pro since it does just help me achieve my goal of escapism.)
Bottom line : I'll continue watching, and really that's it comes down to.
That said I know it won't be for everyone.