Testimonials

There are three things what you need for best way of improving at Go.

(1)Various similar level players,
(2)Good teacher (for commenting your games),
(3)Regular league system (which you can play as serious as a tournament game)
It means that if people can play serious game at least 3 times a week regularly and review all of their game by strong player, then people can improve fast. 
Hwang Inseong, former Korean 1st class Insei, S.Korea-Germany

The insei league is I believe the most successful teaching project on KGS, and possibly better than most American and European baduk academies. 

Andy Liu, KGS and AGA 9d, one of the strongest amateurs in USA

I started out as the weakest player of everyone (the only double digit kyu, i was maybe even 11k at that point), and my real life teacher noted that i probably gained about 2 stones this month even though i wasnt able to play as much as i hoped. (around 8-9k right now), so ive seen the benefits thusfar.
xDragon, E group, USA

So far so good, I have very much enjoyed the lectures I have attended by Alex, and people seem fairly active in playing their games. Also I have gone up one "kyu"
BadukBoris, D group, USA

I have entered the league this month, in group A, and I am really enjoying it! I improved by 2 stones the first day ! Am I joking ? Not exactly. It's just that the motivation the league gives me to play serious games raised my level of concentration. I played again in go clubs and my usual opponents are no match anymore. That should apply mostly only to me I suppose, but still I am happy ^^. I feel that I improve every match, and breakfast give me quick remarks (very short, but efficient) at the end of each simultaneous games, that make them worse it
arlequ1, A group, Japan

Я вступил в лигу, чтобы иметь возможность регулярно играть серьёзные игры, которых мне не хватает в обычной игре по интернету. Турнирная мотивация помогает концентрироваться на партии; регулярные разборы (не только учителями, но и самими игроками после партии) помогают лучше понять свои и чужие ошибки. Не удивительно, что всё это в совокупности позволило мне за три месяца вырасти более, чем на четыре камня. 

stradetch (Георгий Мусин), группа Б

Играть все 44 партии в месяц просто нереально, но 15-20 турнирных вполне можно, причем как показал опыт декабря, нет никаких проблем с поиском соперника. Дело лишь в желании. 
Зато лекций в лиге стало очень много, по сравнению с весной. Я получил разборы всех!! партий за декабрь, причем на все лекции партий все равно не хватает.

Targung (Аистов Алексей), группа С