In the pros, the characters are all amazing. The creators made a good decision by not making any of the characters really perfect. The show's protagonist (or however you want to consider him), Phantom Thief Joker, makes miracles out of thin air. But he also has flaws. He is also hot headed, sometimes denies his shortcomings and can't come to terms with his rival.
Another thing is that all of the characters are memorable. Phantom Thief Joker and Spade probably have the best design in the entire show, but the supporting characters also get some love. Like for example, Detective Oniyama is over the top and has a burning passion to capture Joker. Mister Kaneari is a self-absorbed snob. Spade is what you would probably call a gentleman of sorts. Hashi, Joker's sidekick, just wants to help.
This is not a perfect anime, mind you. While there are only currently four episodes, it would be understandable that some things wouldn't be explained. But there are some mentions of groups or organizations that we are not completely aware of. There is also the problem that sometimes, the characters could get a little annoying to listen to. This was meant for a younger audiences, and you will probably hear some catchphrases being thrown around here and there, which depending on your view, could be tiresome.
But don't let those cons ruin the show for you. This is not a show you can take extremely seriously. It is a fun, humorous show that lives in its own little world, and it executes its characters very well. Sure, sometimes there will be some annoying parts, but that shouldn't deter your experience with it. The season 2 was released last April 6, 2015. I still hope that this will be given another shot.