I was a common poster at the time and my opinion was that I was on the fence. I loved Justin Hartley, but hated everything about his character once he became a series regular. But to be honest, I never once watched an episode of Arrow during its original run. What ended up selling me on the show was that I had a Netflix account and I saw a really convincing cosplayer in the Arrow suit at NYCC. So I checked out the show and was hooked by the end of the first episode. I ended up watching 3-4 episodes a night after work and then caught up to season 2 early on in once I heard the Black Canary made an appearance.
In retrospect, I don't know who different things would have been had I started watching right from the start. One of the things that really hooked me was how each episode would end in a way that made you anxious to see the next one, and after I fell behind in season 2, I watched the last 8 episodes back to back and I appreciated it a lot more than I did watching Arrow and Flash on a weekly basis last season.