I gues i'm going with Kakashi too since he did focus a little too much on Sasuke.
Its hard to tell anything about the rest though since aside from team 10 no one really got any attention. Kurenai could be a great teacher or a horrible one, but we never see any of that since Kurenai herself never really does anything in the manga. --- ..Gwaar... Haaaarr... Haaaaaa... Shoulda brought... more priests... Or some... babies... Dang...
Kakashi did not do that badly with Naruto as some of you are saying He helped Naruto grow mentally a lot and although he failed with that b**** Sasuke and ignored Sakura, he still made himself a good impression in Naruto's head and helped him indirectly more than he is given credit for. Minato is a bada**(I wont even discuss his potential as a teacher, It was kakashi's failure as captain that what happened to obito happened and as for rin well we dont know much about that situation
Hiruzen was a great man who inspired Jiraya greatly although he did favour oro
Kurenai well meh she is a woman and you know the compatibility of kishi and women
Gai failes in everyway as sensi so I pick him He only physically trained lee and nothing else he never gave tenten or neji training that would suit their abilites that's all
Neji did not want any Taijutsu training from Guy since they are both completly different types of Taijutsu. Neji would rather hone his own style than learn a completely different style. And Lee was in definite need of training since he could do absolutely nothing besides throw shuriken. Probably the reason he got a red headband instead of the standard blue.
Guy basically only trained them in the art of team work.
We all agree Asuma is the best teacher. (He also had the worst genin to teach. A sissy, a lazy, and Ino.)
Second comes Guy. Guy is incompatible with 2/3 of his students. He uses taijutsu. Lee uses taijutsu. But Neji is a Hyuga with Gentle Fist while Tenten uses summoning to use ninja tools. Guy does none of that. The one thing he CAN do is build general physical strength across the board. Tenten & Neji have always been shown being annoyed, but what else can Guy do? Attempt to teach Neji about the Byakugan? Give Tenten a last name? No. He can atleast increase their speed or physical prowess to handle the crap they specialize in. And while he may overdo it, he supports teamwork, as seen in the Rescue Gaara Arc.
Kurenai has it even worse than Guy. She's a genjutsu user, given three students who have no need for genjutsu. What the hell can she do? Even then, she tries her best. Whether it's giving support to Hinata when her dad basically disowns her, or helping Shino with his Chunin Exam match. Dunno what she did for Kiba, as it wasn't shown, but she has an uphill battle already. But she doesn't ignore her weak link, Hinata. Her team is mostly used for tracking as well. How does one teach that? If Kishi had shown her team having high genjutsu resistance, I'd say bravo Kishi! But no, Hinata and Kiba get genjutsu'd by Kabuto like everyone else. (Shino didn't though... Hmm)
Then we have Kakashi. Someone PERFECTLY suited to train ALL of his students. He has genjutsu for Sakura, a Sharingan for Sasuke, and ninjutsu for everyone. (Nice job telling Naruto about the clone trick so late, Kakashi...) Yet he focuses on Sasuke. When both Naruto and Sasuke advance, why does he shaft Naruto? Because he sees himself in Sasuke? BAD. He sees potential in Sakura, and knows she's the weak link, yet ignores her? BAD. It's pathetic. No other sensei is so suited for their team, yet fails so hard like Kakashi. He ranks lowest for me.
Everyone else is a good Sensei, imo --- Am I gay? No. I'm just not sex-crazed like you. Man or woman. Elderly or young. Rich or poor. Famous or unknown. I couldn't care less. You're on equal grounds.