For me it's: Cross Game > H2 > Touch.
Touch is rather like an early draft, rough in many places and does lack the pin-point accuracy in both, display of his humour, the baseball related story and the romantic subplots.
Miyuki is much different from those in setup and characters, it's a nice romance story but it offers less of what Adachi is known for. The art is comparatively weak and doesn't improve as much as Touch, also it's a tad too generic compared to other similar stuff. Can't say much about Hiatari Ryouko. Slow Step is on the other hand much like a better version of Miyuki with the things Adachi is best known for, his self-humour and the big spotlight at sports.
Back to H2. The manga is strong, of course. The anime is also quite strong and is a good adaption, with nice animation and they manage to capture Adachi's style very well, however, there's one thing wrong with it. It ends halfway through the manga. The drama doesn't have a lot to do with H2, they took the characters, a few parts of the plot and mixed them with everything Japanese drama are known for and let the whole thing run for 11 episodes. It lacks just lacks Adachi's style and is too much of your generic jdrama.