we go to Tutortime KLT on Sats for 1.5 hrs. i'm ok happy with it, not over the top, but it's ok. the teachers are very enthusiastic, so they teach well. half the class is mandarin and the other half in English, basically a mixture of music, dancing, learning, arts and crafts (the arts and craft are mostly done by the adult really)... a good variety of activities so they don't get bored for that 1.5 hrs. but for actual learning, maybe since we're only going for once a week, it's not that efficient.
Tho, i really liked that my child has learn things such as lining up, cleaning up when we sing the clean up song, staying seated when eating, all those can transfer back to good use at home. it's easier for her to learn those things in a group setting, so i'm most happy about that.