I enjoyed Arrow for the first few years, but I lost interest in it sometime during the 4th season. I haven't seen much of Supergil beyond the episodes of her show involved in cross overs, I watched the first 5-6 episodes of the first season and wasn't really into it.
I think the first two seasons of The Flash were really good. Since then it has dipped in quality, but it's still enjoyable.
Legends, IMO, has consistently had each new season be better than the previous one.
I loved Smallville and I've seen every episode, but I'm not sure I want a reboot anytime soon.