I watched re-zero twice now once in the initial run and then once with the director's cut. Which word of advice if you are wondering what version to go with the director's cut is the way to go as it is technically the finished version. That said I would not recommend re-watching it just for the changes as they are mostly technical details and the new content at the end is also played in episode one of season 2.
I also watched it dubbed the second time around and while I got the usual jarring dissonance you get from switching the dub is satisfactory, not amazing but on par with the subbed version.
As for what I thought of the show initially I loved it based on the last quarter but upon a second watching, I can't say that anymore. I still enjoyed to be sure but it's a big build-up to get to the worthwhile content and 15-16 episodes is a lot to ask to wade through to get to the good stuff.
as others have said whether one can enjoy this show hinges on if you like Subaru or can put up with his bratty generic ass character for the first 15-16 episodes. That primarily is because there is not a lot to talk about with anyone else. Wilhelm was the only character I particularly enjoyed. People seem to love the second season so hopefully, that fleshes out more characters, but again that assumes one can but up with the frankly mediocre start which tries to get value out of all the gore.
a fine show but I am looking forward to the 2nd season much more