It's as simple as: if you like Cross Game, H2, Sunny Ryoko, and (especially) Touch, you'll enjoy this anime for the most part, because of nostalgia and all the tricks Adachi usually pulls to mess with our heart; if you don't like the anime/manga mentioned above, then you won't enjoy watching MIX at all, since it's by far the weakest out of the bunch.
Adachi pulls exactly the same old tricks as he did in the 80s and the 90s, which is why stuff like the casual stalking and creep shots can turn people off, however these tricks are pulled in a self-aware fashion. It's fairly obvious that the author and most of the characters don't approve of these actions and find them creepy, and that they're present 100% for Touch nostalgia points.
This series has nothing unique going on for it (even more than usual). It's tailored specifically for an older audience and die-hard Adachi fans. Overall, it's lighter on the heart-strings, the romance drama is toned down (so far), the baseball games aren't that dramatic, there are no evil coaches and players, and the characters never really break down completely. I wish the characters were more emotionally unstable, but it looks like Adachi held himself back.
The 4th wall breaking is absolutely atrocious though. I guess the author figured that the 80s humor wasn't cutting it in the current times, so he tried to be funny that way, but instead it just breaks immersion and takes away from the little seriousness that's left in the anime.
Finally, this anime feels like something that would come out in 2010. There are too many long and pointless conversations, the screen changes very slowly, there are too many repeated flashbacks and jokes. Simply put, it's very easy to find enough stuff to cut out of the episodes to turn this into a 12 episode per season anime, and the quality would actually shoot through the roof thanks to that. The first 4 episodes of season 2 were especially boring and predictable.
Recommended and rated at 7/10 because Adachi is my favorite author. I obviously have bias and enjoyed this way more than most people would.
