I never read Sir Conan Doyle's Sherlock series so I can't say how any versions of Sherlock played up to it's book predecessors but I will say the Japanese version lacked some depth in many many ways.

I've seen several British versions of Sherlock and enjoyed those. I even enjoyed the US version with Jeremy Miller and Lucy Lu.
When I saw that the Japanese had their version I had to watch.

The first episode was great. I liked how it started off but by the third episode everything became predictable before I can say predictable. There was no mystery in each episode as to 'who dunnit'.

Dean Fujioka's version of Sherlock was good. We didn't learn his backstory until the very last episode. I don't know why Iwata Takanori's character was there. His verion of Watson was so bad! He didn't add anything to the series. The kid who got info for Fuijoka's character was way better than Takanori.
I really despised the detective's character. He was another character that made the series less desirable to watch. The guy who played as the fake Moriya was also really really weak. I didn't understand what his purpose was. The last episode had me scratching my head. It was truly a waste of a watch.

I stuck this out because I've been hooked on Korean dramas. I've enjoyed a lot of Kdramas but is trying to expand my dramas to Chinese and Japanese as well but for some odd reason these two just don't have the skill Koreans have. It's hard trying to like other genres when dramas like this is given.
I just hope they're done with this series. Leaving it as a cliff hanger makes me hope they won't bring back a part two.