In one sentence, it's Den-O done right.
I like that we now have a fresh batch of writers for Rider. Kobayashi, Inoue, and the rest still have good ideas, but as their most recent shows seem to prove, they're either past their prime or don't really care anymore. So now we have W, which isn't so mystery-focused and follows a more case-by-case basis like Den-O. But unlike Den-O, Sanjo knows there is still a plot and has been steadily advancing it as time goes by. So at the moment W is pretty nice. I'm not rushing to watch the newest episode every week like I was in the past, but it's still good enough.
The one thing I really hate is how the Gaia Memories can talk. It's so redundant to press the button to yell out "Cyclone, Joker, etc.", only for the belt to repeat it again. Stuff like this is part of the reason why shows shouldn't become too merchandise-focused. You see the Kuuga and Agito henshins and how relatively simple they are. Non-elaborate belts, all you do is a cool pose. Those henshins look a lot cooler and less silly than some of the later stuff where you have to press a ton of buttons and insert this thing into that before you can transform.